Echoes of Time Lost

---

Shariana watched the fight on the monitor, marvelling anew at the numbers the Daleks were willing to sacrifice for even the tiniest advance. Tens of thousands - hundreds of thousands - were dying out there with every breath she took and yet their ships kept coming. Their sheer numbers would win the War eventually, she was as certain of that as she was of her own name. How could the Time Lords win when the Daleks could lose five million with replacements already waiting to take their places?

Each Time Lord who died could not be replaced and, though their casualties were far fewer, every death brought them one step closer to failure. It had become a war of attrition and the Time Lords could never win such a fight.

The new life that slept beneath Shariana's hearts stirred and she rested a hand on her swollen belly. The child would be the next wave of soldiers in the war, but the years they would need to bring her to maturity and teach her all she needed to know might be too long.

On the monitor another Dalek ship exploded, huge chunks of metal spraying out and setting off explosions in two Dalek ships near it. The activity behind Shariana intensified as pilots at the console manoeuvred their TARDIS out of phase from the flying shards. There was little for Shariana to do. They were a medical and observation post, recording everything for the Matrix and cleaning up whatever was left. The planet that was the focal point of the battle was already a raging inferno and even as she watched it began to break up. The stresses of a war fought in physical and temporal dimensions were becoming too much for local time-space and everything was starting to warp.

Another three Dalek ships exploded and at the same time one of the Gallifreyan ships started to pull away from the battle. Within an instant Shariana knew why. The pilots at the console started shouting, the TARDIS engines screamed and space-time fractured around them.

The temporal concussion hit before the TARDIS could escape and Shariana's head felt as though it would explode. Ripples through the Vortex sent everything in the TARDIS shaking and Shariana fell heavily, her arm crumpling painfully underneath her.

The pain in her wrist and head became as nothing compared to the pain that shot through her belly and Shariana felt the child inside her scream.

---

"Donna!"

Donna smiled to herself and picked up two mugs of freshly made tea. The trick with the Doctor was to always keep him on the back foot. While he tried to regain the advantage in a conversation, she could usually get him to do exactly what she wanted.

"Donna, what is..."

As predicted, the Doctor trailed to a halt as Donna appeared with the tea and he glared at her suspiciously.

"Donna?"

"Tea, Doctor?" Donna said sweetly, holding out the mug.

He took it absently and held out his hand. "What is this?"

"It's a Post It note," Donna said.

"I can see that. Why is there a Post It note with a date written on it stuck to the monitor?" the Doctor asked.

"It's my Mum's birthday," Donna said. "She'll kill me if I miss the party. I thought we could stop by on our way."

"On our way where?"

"Wherever you're taking us," Donna said. "Go on, for me?"

"Twenty-first century Earth isn't really on our way," the Doctor said, but he was already moving towards the console and taking a sip of his tea. "You can bribe me with tea more often, if you'd like."

Donna rolled her eyes. "Don't get your hopes up."

---

Over the months, Donna had learned that nothing was ever as simple as "press some buttons and we'll get there without a problem". The TARDIS sometimes seemed to have a mind of her own. So it came as no surprise to Donna that the Doctor looked slightly abashed when he checked the co-ordinates after they landed.

"Ah," he said.

"Doctor?" It was her warning but not actually angry yet voice, which oddly enough seemed to work better than her angry voice.

"We're a little early," the Doctor said.

"How early?"

"About two days."

On the one hand, that gave her time to do a bit of shopping and buy a decent present. "It was the thought that counted" only worked with other people's mothers. On the other hand, it gave her two days to spend with her mother and as much as Donna loved her, she was uncertain that she could cope with that much unbuffered mother-daughter time unless she and Gramps could escape into the allotments for at least part of the time.

She definitely did not want the Doctor around her mother for that length of time.

"Problem?" the Doctor asked.

"No, no," Donna said quickly. "Of course not."

"You'll have more time with your mum now," the Doctor said. "Proper time with her. People like that, spending time with parents and so on."

"Yeah, they do," Donna said unenthusiastically.

"You'll have a nice break," the Doctor continued. "Come back fresh and raring to go."

"Raring, yeah," Donna echoed. "What will you do?"

"Me? Oh, well, I'll look up some old friends, maybe do a few repairs around here," the Doctor said, scrubbing at his messy hair in the way that always signalled some deep discomfort. "Don't you worry about me, I've got plenty to do here until you're ready."

"You'll spend the next two days brooding in here, right?" Donna said. "Don't try to deny it, I know you."

"Repairs," the Doctor said firmly. "The TARDIS needs repairs that I've been putting off for ages. This couldn't be more perfect."

"Why don't you meet me in Gramps' allotment tonight," Donna said. "He'd love to see you again."

"You really think so?"

"I know so," Donna said. "He always asks what we've been doing and it's not just me that he's interested in."

"If you're sure..."

"Absolutely," Donna said firmly. "I'll see you tonight."

---

Her road had not changed at all since Donna left two months ago. The Atmos stickers had been removed from the cars but otherwise it looked exactly as it had the last time she visited. It was the kind of street where nothing ever changed except, occasionally, for the model of car sitting on the driveways. There was no sign that a few weeks ago - for the residents - they had almost died from the Sontaran clone gas. Donna reflected that the road was like a rubber ball, absorbing everything the world threw at it and bouncing back as though nothing had happened.

It was no co-incidence that Donna carefully planned her day to make sure that she arrived at the house after her mum had left for her weekly bridge afternoon. A morning's shopping had produced a vase, a sweater and some gift vouchers that would hopefully pass inspection for a birthday present, although her bank account was now looking rather low and it had occurred to Donna that at some stage she would be as penniless as the Doctor if she continued travelling with him. Oddly, that thought did not worry her as much as it might have a couple of years ago. How often would she need money on Earth, anyway?

Her key was buried at the bottom of her bag and it grated in the lock when she finally found it.

"Gramps?" she called as she finally got the door opened. "You here?"

There was the sound of hurried footsteps from the kitchen and then Wilf was standing in the doorway, a box of tea bags in his hands and a delighted grin on his face.

"Donna!" he cried. "Sweetheart!"

His hug, still strong, and the smell of wool and fresh air and smoke had always signalled home to Donna and she returned it as fiercely as he gave it.

"Donna, love," Wilf said happily, pulling away to hold her at arm's-length and examine her carefully. "You look well."

"I am well," Donna said with a grin. "You making tea?"

Wilf rolled his eyes – it was obvious to anyone who saw them together where Donna had picked up that expression – and gestured her into the kitchen. "You've always had a talent for turning up at the right time."

"That's not what Mum calls it," Donna muttered, following him.

She shortly had a mug of good strong tea and Wilf had tracked down the secret biscuit stash and treated them both to chocolate bourbons.

"Have I missed anything?" Donna asked, settling at the kitchen table opposite her grandfather.

"Not much," Wilf said. "You were here for the last big excitement. Your Aunt Emily is going to be visiting us from Australia next week so your mum's got me clearing out your old room for her."

Donna wrinkled her nose. "Sorry about that. I can give you a hand if you'd like?"

"That would be lovely, sweetheart," Wilf said. "I think your mum wants most of it gone rather than cluttering up the loft."

"Most of it is junk," Donna said. "I don't even know why I kept it all."

"As I recall," Wilf said, "you protested loudly when we suggested getting rid of some of it after you moved back here."

"Yeah, well," Donna said, rather weakly although she was not admitting it.

One of the things that she had always liked about her grandfather was that he knew when to drop a subject and when not to. It was something her mum had never quite got the hang of and Donna wondered sometimes how someone like Wilf had produced her mother at all.

"So, tell me what you've been up to," Wilf said, eager curiosity brightening his face and making the lines and wrinkles almost melt away for a moment. "Before your mum gets back and tells us off."

They spent the afternoon sorting through the accumulated junk in Donna's room while she told him about all the adventures she'd had with the Doctor. There were so many amazing places she had seen and Donna found that she didn't have the words to describe some of them properly. The gas giant they had spent an afternoon hovering over had been one of the most spectacular things she had ever seen yet it was impossible to convey the wonder and terror that something so huge and violent could produce.

Wilf seemed to understand the lack and somehow Donna found herself telling him all the things that she would never have told anyone else, even the things she wasn't proud of.

By the time the front door opened, there were several black bags in the hallway ready for transport to the tip and a Donna had a small shoebox of possessions to take with her to the TARDIS. The room looked tidy and empty, a guest room rather than a home. Even the mattress was stripped and leaning against a wall, ready to for the men to pick up when they delivered a new one tomorrow. There was no room here for her now. She would lie to her mum and say that she was staying with friends when she visited because that somehow made it easier for everyone. It should have felt depressing but Donna found it reassuring. Her future wasn't here anymore.

The front door banged and a moment later her mum's voice floated up to them.

"Dad!" Sylvia called. "Come and give me a hand."

"Look who's come to visit!" Wilf crowed as he hurried down the stairs to take shopping bags from Sylvia.

"Hello, Mum," Donna said, following him.

The brilliant smile that Sylvia gave her was so unexpected that Donna almost forgot to return her mother's hug.

"Hello, love," Sylvia said quietly and then pulled back, examining Donna critically. "You've put on weight."

---

Supper passed with Sylvia giving her usual criticisms of Donna's appearance, lack of job and apparently directionless existence. Behind her back, Wilf rolled his eyes and made faces and Donna found that she didn't really care what her mother thought anymore. Her life had purpose and what she did now was more important than any secretarial job her mother could find.

"I suppose that you'll be going up to the allotment," Sylvia said as she supervised the clearing of dishes afterwards.

Donna stacked the dishes in the dishwasher and let Gramps deal with her mum. He had always been able to get round Sylvia much better than she could.

"You don't want us around," Wilf said cheerfully. "Don't you usually have Ivy and Emily round for coffee tonight?"

"Yeah, we'd just be in the way," Donna said quickly.

"You're never in the way," Sylvia said, conveniently forgetting that Donna's room had just been cleared for a visit from her sister-in-law. "But it would be easier if you two aren't watching TV in the lounge tonight. Go on, off with you then."

Making a thermos of tea and packing up custard creams and slices of Swiss roll for an evening snack took a little longer than Donna would have liked, but she managed to hustle Gramps out of the door just as Ivy and Emily walked up the path. Donna nodded politely to them and then joined arms with Gramps to march up the hill to the allotment. It was a familiar ritual, something that she had enjoyed since she was a tiny kid and Sylvia had let Gramps carry her off to stay up far past her bedtime staring at stars she couldn't yet pronounce. They dragged the blankets and folding chairs from the shed and set up a comfortable picnic. Wilf fiddled happily with the telescope, checking against star maps until he was satisfied that everything was just right.

"Have you been to a comet yet?" Wilf asked.

"No," Donna said.

"Take a look at that, then," Wilf said, gesturing to the telescope.

The comet was beautiful, a bright light with a faint tail that seemed even more amazing because Donna now knew just how far away it had to be.

"Gramps, if the Doctor asked you to come with us, would you come?" Donna asked thoughtfully after a while

"If I was thirty years younger, you couldn't keep me away," Wilf said.

Donna looked up from the eyepiece. "No, if he asked now, would you come?"

"It's for younger people," Wilf said. "I've heard your tales, I couldn't keep up."

"It's not all running around," Donna said. "We go places just to see them and nothing else happens. Last week we went to this planet where the trees sing and the sky is purple. It was beautiful. He could take you to see that comet and we'd just hover beside it."

Wilf fixed her with a glare. "It sounds like most of the places you go to involve some kind of adventure."

"Quite right too," came the Doctor's voice. "Much more interesting that way."

It was quite amusing to see the way that Wilf straightened up and smiled, almost like a schoolboy given the best treat in the world as long as he stayed on his best behaviour. Donna half-expected him to salute but instead he stood up and offered his hand.

"Good to see you again, sir," Wilf said eagerly.

The Doctor beamed. "Nice to see you, too. Has Donna been telling all our secrets? I know what she's like when she starts."

"She tells me some of the things you do," Wilf said. "She doesn't tell me everything. I think she's try to protect me."

"Gramps!" Donna exclaimed.

"Nah, nothing's ever that dangerous," the Doctor said. "Well, except for that time with the Ice Warriors. And the Graphalax. Maybe that time on Brigadoon III was a little dicey."

Donna buried her head in her hands. The word 'discreet' apparently wasn't in the Doctor's vocabulary and she might have to kill him later.

"Thank you, Doctor," Donna said sarcastically. "Very helpful."

"I try," the Doctor said. "So, what are you two looking at?"

Donna would deny it to anyone who asked, but she really enjoyed watching Wilf as he explained the comet and listened to everything the Doctor could tell him. It was kind of like watching two excited children as they discussed the telescope, the stars and some of the Doctor's favourite (and least likely) planets in the universe. It would always be wonderful to be out there seeing amazing things that she barely had the vocabulary to describe, but Donna wished that she could do more than just tell her grandfather about it all. She thought that he might possibly love it even more than she did if he actually went there.

They called it a night sometime after midnight, Wilf looking slightly sheepish because he knew that Sylvia would tell them both off. Donna sometimes wondered whether her mother realised that she had taken on the mothering role for both of them.

As they walked out of the allotment carrying blankets and thermoses, Donna had a sudden thought.

"Doctor, do you suppose that Gramps could take a look around the TARDIS?" she said. "Just a quick look, without going anywhere."

"Well..." the Doctor said, scratching a hand through his hair so that it looked even wilder than usual.

Wilf failed completely to hide his eagerness.

"Please?" Donna said in her most wheedling voice. "Just a quick one, you know it won't take long."

"I suppose a quick look won't hurt anyone," the Doctor said, turning at the end of the road and marching towards the TARDIS. "Just don't touch anything."

Wilf and Donna exchanged happy looks and followed quickly.

From the outside, the TARDIS looked perfectly normal. A serene blue police box that looked oddly right in its place even though police boxes had not been a part of the street furniture for years. It would never be the most elegant vessel in the world – or look much like a machine capable of all the wonderful things that it could do – but Donna had become fond of it over the months.

It was when they opened the doors and entered that the lie of the appearance became apparent. The light, usually so soft and golden, was a harsh red. Beeps and alarms made a cacophony of noise and underneath it, a bass to the tenors of the alarms, a deep bell sounded sonorously.

"What's all the noise for?" Donna asked, dumping her armload of blankets and the shoebox of belongings on the metal gangway and following the Doctor to the console.

"I don't know!" the Doctor shouted, rushing around the console as he tried to check five different readouts at the same time. "Someone...no, nobody would be doing that. Would they?"

He spun a handle roughly and pulled one of the screens towards himself. Nothing on the screen meant anything to Donna but the Doctor only seemed to grow more agitated when he saw it.

"What can I do, Doctor?" Donna asked.

"Someone is trying to access the Time Vortex," the Doctor said.

"Don't we do that all the time?"

"I know what I'm doing!" the Doctor said. "If I can just track them...Donna, hold down that green button in front of you."

There were three green buttons and a slider with a green handle on the panel in front of Donna.

"Which one?" Donna asked urgently.

"Any of them! All of them!" came the Doctor's unhelpful reply.

Donna managed to get two of the buttons down and she was grateful to see the older hands of Wilf take the other button and push the slider down.

"Tracking..." the Doctor muttered.

Quite abruptly, everything went silent. The light hesitated a moment and then returned to its usual soft glow as every alarm ceased. Donna waited but the bell did not sound again.

"Lost it!" the Doctor cried angrily. "They've stopped."

"Is that it?" Donna asked.

"Maybe," the Doctor muttered, glaring at his screen again and absently winding something that looked suspiciously like a fishing reel. "If I can...no...what if I...?"

"Can we let go now?" Donna asked, aiming for a placatory tone of voice but missing by a mile.

"Hmm? Oh, yes, that won't help now."

Donna and Wilf stood by the console, feeling a bit useless and forgotten.

"Is he always like this?" Wilf asked.

"He likes a puzzle," Donna said. "Too much, sometimes."

"This isn't a puzzle, Donna," the Doctor said. "This is possibly a disaster."

"Yeah, he also likes to be melodramatic."

The Doctor looked up from the console and even Donna had to admit that he looked more than usually frazzled.

"Maybe if you explain," Donna began.

"Someone is trying to access the Time Vortex," the Doctor said.

"So you said. What's so bad about doing it? We do it all the time."

The Doctor ran his hand through his hair, making it stand on end even more than normal. "We have control when we do it. I know what I'm doing."

He must have realised that Donna and Wilf were not following the gravity of the situation because he heaved a huge sigh and looked as though he was trying to regain some calm.

"When we access the Vortex, it's like..." he looked around for a moment, unable to vocalise the comparison. "It's like the TARDIS is a lift going into a tunnel through pre-built access routes. Well, not exactly like that because we enter the Vortex in a different place every time we travel because we rejoin local time every time we land, but you get the idea."

Donna and Wilf nodded.

"Whoever is doing this is drilling a hole into that tunnel," the Doctor said. "And holes are bad. Very bad. Particularly if the tunnel is filled with something that shouldn't come into contact with normal space."

"So it's like someone drilling into a huge gas main to travel," Donna said. "Only the gas is all going to escape through the hole and cause a massive explosion."

"Exactly like that!" the Doctor said triumphantly.

"Right, that's bad," Donna said. "What can we do?"

"Stop them," the Doctor said, "before they actually succeed."

"Any ideas how we do that?" Donna asked.

"Not yet," the Doctor said.

"He'll think of something," Donna confided to Wilf. "He always does."

"I know, love," Wilf said.

The Doctor continued pressing things on the console and Donna was about to offer to escort Wilf home when she noticed a small light flashing. She was sure that there was not normally a light flashing there. It was green, which in normal Earth logic would mean something good but who knew how Time Lord logic worked?

"Doctor," Donna said. "Is that supposed to be flashing?"

The Doctor looked at where she was pointing and for just a moment he stopped completely, his face blank. It was such a brief moment that Donna might have thought she had imagined it except that he then went into a slightly frenetic flurry of button pressing and dancing around the console that seemed quite deliberate.

"Yes, yes, quite normal," he said quickly. "Now, if I do this..."

He pressed several buttons and set a dial twirling.

"And this," he pushed two levers, "I should be able track the source the next time someone attempts to access the Vortex."

"They'll try again," Wilf asked.

"Oh, yes," the Doctor said. "They always do. Human curiosity. Marvellous thing, except when it destroys the universe."

Donna stared at the flashing green light. It was such an innocent little thing and yet the Doctor's reaction had been completely weird. She had learned a few things about him during their travels and she knew that he would refuse to tell her what it really was. Avoiding topics was the Doctor's speciality. It nagged at her, though, because the Doctor only avoided something when it was really important to him and it usually ended badly.

"Time to get your grandfather home, Donna," the Doctor said. "Can't have your Mum sending out search parties, can we?"

"No, I supposed not," Donna said distractedly. "You'll be OK?"

The Doctor grinned. "I'll call you if anything happens."

---

Pain ripped through Shariana's belly again but she did not have the energy to do more than whimper. It was taking too long, the child would never come and she would fail.

There was nobody to attend her. The medical bay was filled with men and women rescued from the disaster and there were not enough medics to attend all of them. Automated systems kept them filled with drugs to dull pain but those same drugs might harm the child. Three had already regenerated but they were doing no better than their fellows. The disaster had torn time and space around them and the newly regenerated Time Lords were too fragile, vulnerable to the forces that had surrounded them even though it had only lasted a few short moments.

Sweat poured from Shariana and she wondered how she could possibly birth the child alive.

---

The console room was slightly ajar when Donna got up in the middle of the night for a cup of tea. That was not unusual - the Doctor never seemed to need much sleep - but it was unusual for the lighting in the console room to be so low. The sliver of light usually lit her way down the corridor to the kitchen. Donna told herself that whatever he was doing was none of her business but she set out a second mug anyway and checked that her dressing gown was tightly belted. The kettle whistling on the stove was ridiculously old-fashioned especially in an alien time ship. It was a comforting sound, reminding her of childhood Saturday mornings when Dad made a pot of strong tea and her mum cooked breakfast while Donna watched Swap Shop and set the table.

Donna made the tea, steeping the bags in the mugs until it was good and strong, and then took them to the console room. She nudged the door open and peered around until she saw the Doctor sitting in a corner with her little shoe-box of possessions strewn in front of him. The deep breath she took before shouting at him was abruptly deflated when she saw the expression on his face.

"Doctor?" Donna asked.

The Doctor looked up and it was as though a mask fell across his face, a cheerful grin that did not reach his eyes and might have fooled anyone who had not spent weeks travelling with him.

"Donna!" he cried. "And tea. It's the answer to everything, tea is. Well, some might argue that the answer is 42 but they've never left Earth. If you've left Earth then you'll know that tea is the answer and you make a fabulous cup."

He sprang up and loped over to take a mug from Donna, inhaling deeply with a slightly manic look.

"Doctor, is everything OK?" Donna asked.

"Absolutely! Couldn't be better!"

"It's just that you've been a bit weird since that alarm," Donna said. "You'll find whoever is trying to time travel, you always do."

"Definitely," the Doctor said. "I'll have them tracked the moment they try to re-open a connection to the Vortex."

"So why are you sitting in the dark with my stuff?" Donna asked, not quite managing to keep the irritation out of her voice.

Really, it was like pulling teeth to get the Doctor to actually tell her things sometimes.

"That's yours?" the Doctor asked.

Donna did not buy the innocent look. "You know that it's mine. Why else would it be in a shoe box marked with my name?"

"How long have you had it?"

The Doctor looked a long sip of his tea and Donna suddenly had the feeling that he was readying himself for something nasty.

"Forever," Donna said. "It's just junk from my room at home. Mum wants me to get rid of it so she can use the room for something else."

"So you don't know where any of it came from?"

"Some, not everything," Donna said. "Most of it's just been in drawers for years but I couldn't throw it away. You know, photos of dead aunts and bracelets from friends that went on holiday to India."

The Doctor frowned into his tea.

"Is anything wrong?" Donna asked.

"I don't really know yet," the Doctor muttered, then the smiling mask appeared again. "Still, nothing to lose sleep over. You should really get to bed, big day tomorrow. How old is your mother going to be?"

"Twenty-nine according to the cake," Donna said. "You're not going to tell me what's going on, are you?"

"Probably not," the Doctor said. "Not yet, anyway. Maybe later."

Donna had always been deliberately incurious until she met the Doctor. It had been a boring life, but an easy one and every now and again she yearned for that simple life to return. The problem was that now she knew what was out there, it was impossible to ignore it all and she knew deep down that her life was better for it. Still, as Donna crawled into bed and swallowed the last of her tea she knew that an incurious life had definitely contained more sleep.

---

The alarms went off as Donna was eating her morning cereal. She dropped the spoon in the bowl and ran for the console room as the deep bell began tolling through the TARDIS again. The Doctor was already running around the console pressing buttons and tweaking dials with mad energy, muttering under his breath as he went.

"Donna!" he cried as he spotted her. "Just in time. Hold that purple lever in place, could you? Keeps slipping."

She pushed the lever up to the top and held it there, a harder task than it looked because it really wanted to move around wildly. Slipping did not cover it.

"Are you tracking them?" she asked.

"Getting a reading," the Doctor said, pulling a monitor towards him. "They're somewhere in Islington, I have an address!"

"Can you stop them?" Donna said.

"Not from here," the Doctor said, just as the red light flickered back to gold and the alarms and bells ceased. "They've stopped."

"Did they do anything serious?"

The Doctor shrugged. "Nothing the Vortex won't heal, this time. But they're getting closer, Donna. They'll get there eventually – probably very soon – and then it will be too late."

"What's the plan?" Donna asked.

"Well," the Doctor said slowly. "Go there and stop them?"

---

"It's all right, I'm here now."

At the touch of Kainel's hand on her cheek, Shariana pulled herself out of the foggy haze that she had drifted into. His familiar face was streaked with dirt and blood and he looked more exhausted than Shariana had ever seen him before. He was the most wonderful thing in the world and she managed to smile at him.

"She's dying," Shariana whispered.

"We're on our way to Gallifrey," Kainel said, "and Territha is going to help you. It will all be over soon."

The medic, Territha, looked worse than Kainel but she smiled reassuringly.

"She's too early," Shariana said. "She's too tiny."

Territha hushed her and said, "Try not to worry, she won't die."

There was a tiny pin-scratch on Shariana's wrist and something cool began to flow up her arm, chasing away exhaustion.

"You'll save her?" Shariana asked.

"I'll save her," Territha said. "She just needs a little help."

The drugs brought calm and hope and dragged Shariana into sleep before she could say another word.

---

Free Internet at the local library was a marvellous thing, particularly when the TARDIS proved to be worse than useless with things like information on businesses. It could happily provide reams of information on other planets, important historical people and technology developments, but the only thing it could tell Donna about the address the signal had come from was that the building was owned by Sigma Research Inc. Nothing on what Sigma did or how long they had been in existence, not even what their research was on.

The Doctor looked a little put out at the lack of information. Donna tried not to look smug as she marched them down Dukes Avenue and found the computer terminals. Google proved to be her friend and happily spat out information on CEOs, company history and research papers.

"Bioengineering," the Doctor read out. "Virology, immunology, genetics and gene mapping. What is a company like that doing with time travel research?"

"Branching out?" Donna suggested.

"Mmm," the Doctor said. "Maybe."

"Do we have a plan?"

"I think we might," the Doctor asked, flipping through the pages that Donna had paid a small fortune to print.

---

The Doctor never went for subtle if he thought that brazen would work. Annoyingly, it worked nine times out of ten so Donna could never complain. Obviously she planned to mock him suitably the next time it didn't work, but this would not be that time.

Sigma Research Inc. was based in a non-descript building that looked just like the buildings to either side. It was one of the newer business complexes that sprang up around London whenever something not quite as old as everything else needed knocking down. Donna thought the area might once have been warehouses, the kind that got old and broken before someone got careless with a match and the whole lot went on fire just in time for a developer to snatch it up at a rock-bottom price. On either side there were buildings with futuristic signs - or what would have looked futuristic circa 1998 - and Sigma's sign looked quite restrained in comparison. Just a Greek letter with the company name across it in neat type. Donna had always figured that the more successful a company was, the more understated its logo looked.

They marched up to the receptionist and the Doctor flipped open his psychic paper.

"Doctor Jones," he said cheerfully. "Professor McGlaughlin invited me to tour the facility the next time I was in town and I'm in town. Thought I'd drop by, you know how it is."

The receptionist was blonde and pretty, dressed in a black M&S suit that had probably been quite stylish five years ago but now just looked a bit dated and drab.

"Do you have an appointment?" the receptionist asked, sounding slightly confused.

"Not really," the Doctor said. "But I'm sure he'll be delighted to see me."

"Um, OK," the receptionist said. "Doctor Jones?"

"That's me," the Doctor said.

The receptionist dialled a number and had a brief conversation with someone that was just too quiet for Donna to hear.

"The Professor will be down shortly," she said when she put the telephone down. "If you could wait over there?"

The chairs that she gestured to looked uncomfortable and grey, but the Doctor beamed and bounced over to them. Donna trailed behind him and, out of habit, picked up a magazine as she sat down. She flicked through it, but 'Virology Journal' was just a bit out of her depth.

"Doctor," she whispered. "Have you actually met this guy?"

"Professor McGlaughlin?" the Doctor said. "Never met the man in my life."

"Won't he notice?" Donna said. "The Health and Safety thing would have been much easier to fake."

"Most scientists at his level have two things in our favour," the Doctor said. "Arrogance and absent mindedness. We wouldn't have got past the receptionist with the Health and Safety story."

Donna muttered "It worked once" under her breath just as a door opened behind reception. The man who came through did not look like a typical absent minded scientist. His suit was rather smart - Italian, probably - and his silvering hair was beautifully cut to highlight the colour and de-emphasise the receding hairline. Donna automatically straightened and then kicked herself for the instinct.

"Professor McGlaughlin," the Doctor said, meeting the other man with an enthusiastic handshake. "So good to see you again."

"Good to see you too, Doctor Jones. And I see that you've brought your, ah, assistant...?" the Professor trailed off inquiringly.

The Doctor grinned. "Miss Noble. My secretary. I was in town for the lecture at the Institute and we have a spare morning. Thought we'd drop by."

"I have to admit that I can't quite remember when we last met," McGlaughlin said. He had just the hint of a Scottish burr in his voice. "You know how these conferences blend."

"Oh, yes," the Doctor said. "Sometimes I forget which city I'm in! It was the symposium in Berlin, last autumn. You presented your paper on predicting antigenic shift in H5N1. Marvellous piece of research, I thought, particularly for such a small company. You promised me a tour of the facility the next time I'm in town."

Whether it was the flattery or the way that the Doctor always sounded so plausible, the Professor's expression cleared and he smiled.

"I'd be delighted," he said. "Obviously there are a few areas that we can't go into - company secrets and all that - but I've got a few things you might be interested in."

"Wonderful!" the Doctor said. "Would it be alright if my secretary came with us? She's a marvel for retaining details and reciting them to me later."

"Of course," McGlaughlin said. "I'd be quite lost without my Carol. Would you follow me?"

Donna trailed behind as the Doctor and the Professor began chattering about viruses and vaccines and chemicals that Donna had never heard of and hoped she wouldn't be asked to pronounce any time soon. The facilities were pretty much what she expected: lots of sterile white rooms, people in hazmat suits behind glass in some places, scientists in white coats looking very intently at graphs and diagrams that meant nothing to Donna. It was way beyond O-Level biology. They could have been doing almost anything and she would not have known whether it was out of place in those labs.

The Doctor managed to look suitably excited about everything and Donna sensed that Professor McGlaughlin was warming up to him. People seemed to fall into two camps around the Doctor: those who liked and admired him (or possibly more) and those who found him profoundly irritating. It was always useful to keep the people in charge of things in the first camp for as long as possible. Donna sometimes wondered why the Doctor seemed to go out of his way to annoy people instead.

The tour ended eventually and the Professor invited them up to his office for a cup of tea. It was a bright, airy office with vibrant paintings on the walls that looked like they might be psychedelic viruses. Donna usually associated brilliant scientists with cluttered, dark offices but it appeared that McGlaughlin was trying hard to break out of the stereotype. Most scientists also did not wear expensive Italian suits and get good haircuts. Perhaps he had been so absorbed into the role of CEO that the usual rules no longer applied.

"So, why are you really here?" McGlaughlin asked when they all had cups of tea and Donna had pinched the only chocolate bourbon from under the Doctor's nose. "I'd be flattered if you really were here to look at my research, but Carol tells me that there was no Doctor Jones at the Berlin conference and she's usually quite accurate in these things."

He fixed Donna with a penetrating stare.

"I'm sure you'd agree, Miss Noble, that keeping track of these kinds of meetings is very important in our line of work."

Donna swallowed hurriedly. "Absolutely."

She tried not to look like she was swearing inside her head.

"Ah," the Doctor said slowly. "Yes. I hoped that you wouldn't notice."

"I did."

"Yes. You did."

"Why are you here, Doctor?" McGlaughlin asked. "The truth, this time."

The Doctor's smile was slightly lopsided. "The truth? Well. The truth is that I heard you were expanding your research. Or perhaps changing the focus."

Both of McGlaughlin's eyebrows shot up. "And where might you have heard this?"

"Oh, word gets around," the Doctor said. "Our community is quite small, after all. You've been recruiting physicists and that's not at all a normal practise for a company like this."

"I might, perhaps, be considering some diversification in our portfolio," McGlaughlin said and Donna was sure that he looked a little sick.

"How do your shareholders feel about that?" the Doctor asked.

"As I own 90% of the shares in this company, I feel quite hopeful about it," McGlaughlin said. "We're a niche company, Doctor, and would like to take us out of the niche and into the global marketplace."

"Can I ask what you're diversifying into?" the Doctor asked.

McGlaughlin smiled smugly. "I think not, Doctor Jones. Now, if you'll excuse me, I have a lunch with some investors that I really can't be late for."

They were back out on the street in record time and the Doctor strode towards the nearby Tube station quickly. Donna's heels clicked loudly as she hurried after him.

"How did you know about the physicists?" Donna asked.

"I didn't," the Doctor said. "It was a hunch."

"Doctor, what were you going to do if he'd denied it all?" Donna asked.

She was in no way upset, obviously, no matter what she thought of the Doctor's sanity and how hard her heart was beating.

"Oh, I would have thought of something," the Doctor said airily.

Donna snorted.

"Still, we got something out of that," the Doctor said.

"Apart from not getting kidnapped, knocked unconscious or experimented on?" Donna said.

The Doctor waved a metallic card with a wide grin. "Access. We'll go back tonight, take a poke around and see what's really going on."

"After Mum's party," Donna said. "She'll kill me if I miss it."

---

The alarms went off mid-afternoon as Donna was attempting to wrangle the wrapping paper into something approaching smart on the new sweater she had bought for her mum. She was forced to run to the console room with the Sellotape still wrapped around her right index finger.

"Is it them again?" she asked.

The Doctor rushed around the console to the monitor, frowning intently.

"What are they doing?" Donna asked, pulling at the Sellotape.

"Trying to destroy space time," the Doctor said irritably.

And then, just as abruptly as they started, all the alarms and bells stopped. The console room lights returned to their usual restful gold and Donna's ears rang in the silence.

"Did they do it this time?" she asked, her voice sounding unnaturally loud.

The Doctor sighed. "No, but they're getting closer. It's just a matter of time."

"How much time?"

Shrugging, the Doctor pushed the monitor back into its usual place. "I wish I knew, Donna."

Donna tugged again at the Sellotape and the roll pulled away and fell on the floor with a clang.

"What time is this party?" the Doctor asked.

"It starts in," Donna checked her watch, "an hour. I should be out of there by eleven. Maybe earlier if nobody keeps Mum out of the sherry."

As she stood up, Sellotape a tangled, sticky mess in her hand, Donna noticed that the light was still blinking green on the console. Next to it sat her shoebox of stuff from the house. A small fobwatch had been taken out and abandoned on the console. It was a bit tarnished and the etching on it sort of blended in with the silvery-black coating. Donna vaguely remembered it kicking around her bedroom for years and she had no idea why it hadn't gone into a jumble sale ages ago. She had never quite been able to bring herself to do it, shoving it into drawers and leaving it on her dresser until she worked out what to do with it.

"Why are you looking through my stuff again?" Donna asked.

The Doctor suddenly became terribly absorbed with something on the console. "No reason. I got curious."

"Ri-i-i-ight," Donna said, drawling out the word in her most disbelieving voice.

The Doctor flashed her a quick grin and continued to be absorbed with the console. Donna gave up and decided to do a bit of research on her own the next time she had a free ten minutes.

---

The baby was tiny and Shariana marvelled that she found something so small and wrinkled and red to be so beautiful. Yet she was beautiful, from her puckered brow to the tiny feet that cycled in the air as though she was already longing to run.

"We did well," Kainel said.

"She's healthy," Shariana said.

There was still pain where they had cut the child from her, but Shariana could bear it easily now that the child was safe and well. The drugs were better used for the survivors. The three who had regenerated would never again feel pain, but there were many others who had been injured and none wished to regenerate if they could heal instead.

"How many did we lose?" Shariana asked.

"Too many," Kainel said. "We recovered some, but we lost three vessels before anyone could lock with them."

"How many did we kill?" Shariana asked fiercely.

Kainel's face clouded. "Not enough to change anything."

They were silent for a while, staring at the miracle of their beautiful baby resting in the tiny cradle next to Shariana's bed. She seemed much too small to survive their world.

---

The party went about as well as Donna expected. Her mum looked fluttery and happy at all the attention and remembered to thank Donna before mentioning that the shade of red in the new sweater didn't quite go with her new trousers. The food was bland but edible, Aunt May's trifle was so alcoholic it made Donna dizzy to stand near it and Betsy Myers topped up Sylvia's sherry so often that she was totally plastered by ten. Donna was glad that she had an excuse not to hang around for the clear-up. Sylvia could be a very stubborn drunk and did not like being poured into bed when was sure that the party could keep going if the room would just stop spinning.

Donna sometimes wondered whether that was what she would have been like later, if the Doctor had not appeared in her life. It had seemed like quite a nice life before she saw the universe. Then she would dismiss the thought because the idea of not travelling in the TARDIS made her quite depressed.

The console room was empty when Donna got to the TARDIS. She spotted her box of things still on the console, the battered old watch now sitting beside it with a wire wrapped around it that trailed off underneath the plinth. Donna picked up the watch and stared at it, trying to see what was so special about it. The watch was nothing special. It felt like ordinary cold metal against her fingers, not even the faintest vibration coming from it and she had put it back on the console before she was really aware that it was what she would do.

Donna did not like mysteries, or at least not the kind where she was left out.

The Doctor had shown her how to access some of the TARDIS databanks weeks ago, muttering something about researching their destinations so that she could wear more appropriate clothing.

"More appropriate clothing my arse, Mr Pin Stripe Suit At All Times," Donna had said under her breath.

The TARDIS translation circuits meant that, even though Donna was sure that everything on the keyboard and screen were in Gallifreyan, she could understand it all and it was hard to even remember that what looked like curvy English was nothing of the kind. She tried a search for 'watch' at first, but it brought back so many results that she immediately started adding other parameters.

It took her a couple of minutes before the monitor displayed a short list of possible references. She dismissed all the ones relating to Earth historical dress immediately and picked the one marked technical. It was a long, complicated article on something called a chameleon arc but Donna had barely read the opening sentence when the Doctor rushed into the room.

"Ready?" he asked, pulling on his long (and not terribly subtle for night-time break-ins) coat.

Donna jumped and turned.

"Are you OK?" he asked.

"Yeah," she said. "You just startled me, that's all. Give me two seconds, I need to change my shoes."

It took her more like thirty seconds to kick off her heels and tie the laces on her trainers and Donna forgot completely to close down the data search when she left. She found the Doctor staring at the monitor when she returned with an expression that Donna thought might have been fear, if she had believed that there was anything the Doctor was afraid of.

"Donna," he said slowly.

"I got curious, OK?" she said defensively. "You keep acting all weird - more weird than normal - around that watch."

"Did you read any of this?" he asked.

"You interrupted me before I could," Donna said.

His expression grew paler, if that was possible, rather than looking relieved. "We'll talk about it later, alright?"

"Uh, yeah," Donna said. "Later."

It was the haunted look that worried Donna and she nearly demanded that they talk about it right here and now, except that the world might end before he could explain if they didn't get a good look around at that lab. He was quiet all the way to the Sigma building, which was odd because taking the Tube could usually guarantee a rambling monologue on the delights of humanity and how many other underground train systems he had tried and why London in all its squalor and dingy dignity had every one of them beaten. That made Donna worry, even though she would normally be telling him to shut up and asking the world in general why she hung around with such a pretentious prat.

Argyle Street was dark and quiet, the lamplight eerie rather than comforting and no sign of life anywhere. It was the kind of place that was busy and bustling by day but once businesses closed there was no need for humanity to enter it. Donna had always found places like this unnerving after dark. It was the reason she had been so glad to have Lance when she worked late in the City or tried to make sure that there were girlfriends to walk with if Lance begged off with a meeting.

Now that she knew what he had been, Donna sometimes wondered whether those excuses had been real. Had there been someone else out there that he really did care for? Or had there been someone else that he had used, someone that he didn't actually hate but used for sex and company anyway? He seemed too selfish to have had a lover that he genuinely felt for.

The building where Sigma Inc. was based was as dark as the others, the logo stencilled into the windows barely visible. Donna could see the blinking lights of an alarm system and guessed that there were human guards somewhere, but obviously nobody was expected to walk in through the front doors at this time of night. There was an alley beside the building and that was where the Doctor led them. A small, plain green door set into the wall halfway down was the only entrance and the Doctor's stolen card let them open it without any problems.

"Cameras?" Donna asked.

The Doctor grinned and held up a small silver box inset with a small flashing blue light. "Confused. Nobody will see us."

He looked very pleased with himself and Donna guessed that he had spent the evening working that out.

The narrow corridor that the door led into was slightly tatty, with only every third light on and no decorations. Nothing like the wide, bright hallways decorated with artwork that Donna had seen during the tour earlier. Her trainers made no sound on the grey lino.

"Do you know where we're going?" Donna whispered.

The Doctor pulled out his sonic screwdriver and it made a quiet whirring sound as he pointed it in various directions. Something about the sound must have been different to the Doctor - although Donna could detect nothing - because after a moment he marched down the corridor with the screwdriver held out before him. Donna followed as he chose a right-hand corridor part way down and then stopped beside a door. The stolen card again allowed them through into a stairwell and the Doctor led them down several flights before uttering a small 'aha' and opening another door just a crack. He peered through cautiously and then opened it properly, beckoning Donna through.

This corridor was much like the one upstairs, except all the lights were on brightly and they emphasised the drab, institutional paint and the concrete that now replaced the lino. The air down there was chilly and a little damp. Donna's breath fogged before her. Their destination was the first door on the left. The Doctor put the sonic screwdriver in his pocket and listened for a moment, his ear pressed against the metal surface and a look of intense concentration on his face.

Donna gestured to convey "Can you hear anything?" and the Doctor shook his head.

Either he could hear nothing or her sign-language needed more work. Donna hoped for the first option.

The card swiping through the reader and the faint beep and click of the door release sounded very loud. It was hard not to imagine guards sweeping through the corridor as soon as they inched the door open. Nothing happened: no bells, no guards, not even a dimming of the lights and Donna released a breath she had not even realised she was holding. The Doctor eased through the door slowly, pausing there for a long moment before allowing Donna to join him.

She quickly saw the reason for his caution. It was a lab filled with gadgets and gizmos and only dimly lit so that it was difficult to see at a quick glance what was equipment and what might be a person. Nothing in the lab moved and it felt as empty as everywhere else in the basement area. The Doctor closed the door behind them and began examining the nearest pieces of equipment. Donna wandered further into the room, ignoring most of the apparatus and searching for any papers or files that might be around. Although there were odd scraps with notes scrawled across them, none of it looked terribly helpful unless the Doctor had an interest in someone's tea requirements. There were stained mugs on the benches and browning apple cores in a bin in one corner. One mug was half-filled with cold tea, not appetising but to Donna's practised eye the milky film over it was only a few hours old.

"Don't people in secret labs usually work at night?" Donna asked quietly.

"If they want to blend in with everyone else entering and leaving the building, they don't," the Doctor said absently. "Nobody comes down this street at night."

"Oh."

"Donna, come and look at this," the Doctor said.

"Found something?" she asked, weaving her way through the lab to the Doctor.

He was next to a large machine that stood on the floor and was taller than him by a couple of inches. It was easily the biggest thing in the room. Bits of metal plating had been attached to the exterior, possibly in an attempt to protect sensitive parts, but most of the structure was exposed to reveal wires and circuits and metal pipes that twisted in confusing architectures. A panel of lights and switches faced Donna with a small black keyboard beneath it.

"What is it?" Donna asked.

The Doctor passed the sonic screwdriver over it, brows raising at whatever it detected. "It's a Vortex manipulator. A crude one, no real controls to it, but they're not far from getting it to work. Not far at all."

"And that's bad?"

"That's very bad," the Doctor said. "No controls, no safeguards, nothing to protect the Vortex or to protect the people in this lab from the Vortex. They appear to be trying to create a portal rather than working on a way to travel through the Vortex."

"Let me guess. A portal would allow all the dangerous...whatever...in the Vortex to get out without any way to stop it," Donna said.

"Pretty much," the Doctor said. "It would be two-way, but unprotected travel through the Vortex is very dangerous. People are always looking for short-cuts when they try this."

"Other people have tried this?" Donna asked.

"Oh, yes, there are always societies trying to master time travel," the Doctor said, almost cheerfully. "They're normally so far off-track that they're only really a danger to themselves. My people used to stop them before they got this far, though."

Donna sniffed. "Sounds about right. The haves trying to stop the have nots getting something."

The Doctor did not reply, instead bending closer to the mechanism and tracing a wire with the tip of a finger.

"There's some very advanced technology in this," the Doctor said thoughtfully.

"Too advanced?" Donna asked.

"Definitely."

"Can we destroy it?"

The Doctor shook his head. "Not yet. I don't want to alert anyone that we know what this is until I know who's behind it."

"You think there might be aliens here?" Donna said.

"Oh, yes," the Doctor said. "There have to be. A few of those components shouldn't even be invented on Earth for at least six hundred years. It's aliens or time travel and aliens would be the least problematic of the two."

"Why?"

"Paradoxes," the Doctor said. "They're very messy to clean up."

"So what do we do?"

The Doctor reached into the device and there was a quiet click as he removed something. Then he swiftly rearranged a few wires, attaching them to different terminals, before buzzing the sonic screwdrivers at one circuit for a couple of seconds.

"There, that should slow them down a bit," the Doctor said. "They'll figure it out eventually, but we've bought ourselves a bit of time."

Walking out of the building was nerve-wracking. At every corridor turn and stair landing Donna expected to find a guard in front of them or hear alarms sounding. Even though they walked slowly and carefully, Donna's heart was racing when they finally closed the green door in the alley and heard the quiet click as it locked. Leaving a building when someone already knew there were intruders was much easier than leaving undetected, but Donna knew that the Doctor was right about buying themselves some time by not making their sabotage obvious.

The Doctor grabbed her hand when they turned the corner out of sight of the Sigma building and they ran to the Tube station, laughing with the exhilaration of the night's adventures.

---

The Doctor pulled the mobile phone out of his pocket as soon as they got to the TARDIS. Donna picked up the fobwatch and glared at him significantly.

He held up a finger and at the same time said, "Martha Jones!"

Obviously Martha was not entirely happy to be woken halfway through the night because the next thing he said was, "Ah, yes, sorry about that."

There was a pause and then he said, "I need your help. Something that your UNIT contacts might be able to help me with." Another pause and then, "No, you don't need to tell them that I'm here. I just need some information. They'll go in guns blazing and then we'll never know."

The pause this time was longer. Donna rubbed her eyes, which were starting to burn from tiredness.

"Martha, thank you," the Doctor said eventually. "I promise that this will be worth it. Tomorrow morning?"

He waited for an affirmative and then hung up.

"You promised that you'd explain what this is," Donna said immediately.

"I know," the Doctor said. "I promise that I will, but it's not a discussion to have when we're tired. Tomorrow morning, I give you my word."

Donna considered for a moment and, while a part of her was desperate to know what could make the Doctor so afraid, the sensible part of her knew that he was right.

"I'll hold you to that," she said.

---

"We've been diverted," Kainel said.

Shariana had moved from the medical bay to her own chamber a day after the baby's birth, preferring her baby away from the dying and injured despite her small size. The baby was already filling out slightly, looking a little less wrinkled even though she was barely seventy hours old.

"Why?" Shariana asked.

"We're making another push," Kainel said.

"What? We have injured here, we need to get them back to Gallifrey."

"Everyone has been diverted. The planet is being emptied, we're throwing everything into one last strike," Kainel said.

Shariana's heart stilled and she stared at the little cradle with her precious, precious bundle of life.

"All of us?" she whispered.

"Gallifrey is lost," Kainel said. "The orders came from the President herself."

"Where are we going?"

"Arkadia," Kainel said.

---

Donna liked Martha. She could not quite understand why Martha had been so fixated on the Doctor for a while, but other than that she thought Martha was bright, funny and a good laugh. She could even understand why Martha had given up the TARDIS lifestyle. Staying on Earth held no appeal to Donna, but she sometimes wondered whether anything could happen that would make her change and she hoped that she never faced that.

Despite liking Martha, Donna felt sure that dealing with Martha before her first cup of tea on an empty stomach was not right. Martha was too cheerful, too awake and too happy for this early in the morning. The only saving grace to her was that she had brought croissants and they were the really good, really big ones from the bakery on the high street.

Donna even made enough tea for Martha and the Doctor as a sort of thank you.

"So, what did you find?" the Doctor asked as Donna spooned sugar into her tea.

Martha grinned. "Aliens. Possibly."

The Doctor looked equally excited. "Really?"

"Something came down just outside Reading about eight months ago," she explained. "It looked like a small satellite on the tracker, but UNIT checked it out just in case."

"Not a satellite?" Donna asked.

"Not a satellite." Martha paused to take a large bite out of a croissant. "We thought that it was too small to carry anything living. It was definitely alien and there was a bit of organic residue inside, but it was totally burned out. The labs haven't been able to reconstruct any of the technology, the damage was that bad."

"So it was marked unimportant and you moved on," the Doctor said.

Martha nodded. "Yes. There were some other things happening at the time - classified things - and UNIT couldn't justify the resources to do anything else."

"It always comes down to money, doesn't it?" the Doctor mused.

"That scan you sent of the circuitry on the Vortex device matches a section of the crashed object," Martha continued. "That's how I could identify it. We had no idea what it was, but the scientists speculated that it might be a part of a control system. The difference is that your circuit is made from Earth alloys and our circuit included an alloy never seen on Earth before."

She passed over a sheet of paper covered in squiggles.

"Can you make anything of that?" Martha asked.

The Doctor put on his glasses and studied it for a while, brow furrowed.

"It's Pathium," he said eventually. "Common alloy in the Bedruga Cluster. Shouldn't get to Earth for at least two thousand years. But there are over thirty different planets in that region that could have built your crashed satellite."

"So it's not that helpful," Martha said, looking a little deflated.

"Well, it's not entirely unhelpful," the Doctor said brightly. "We've narrowed down our aliens and they're trying to replicate their technology on a planet that's several hundred years behind them, which is going to make it harder to succeed. It doesn't tell us why they're experimenting with time travel. None of the cultures in that region have any history with it."

That did not cheer Martha up much, but Donna thought that Martha was a bit of an over-achiever and it was good for her not get the answer every time.

"I should probably go," Martha said after a pause. "You know, things to do, fiancés to visit."

"No, don't go," the Doctor said quietly.

He had his serious look on, the one that Donna privately associated with fire and death and implacable fury. It was something she rarely saw and she put that down to Martha, in part, because she thought that was something he had almost lost himself to when she first met him.

"What's going on, Doctor?" Martha said.

He reached into his jacket and put something on the table. The fobwatch. Donna was surprised to see Martha go pale as she looked at it.

"Where did..." Martha trailed off and looked at Donna. "It's yours?"

For the first time, Donna felt a chill down her spine as she nodded. "What is it? The Doctor's been acting weird ever since he saw it."

Martha and the Doctor looked at each other, one of those looks that people get when they have spent time together and are debating who should deliver some bad news.

"It's the receptacle for a chameleon arc," the Doctor said eventually.

"I got that much from your data-thingy," Donna said impatiently. "What's a chameleon arc?"

"It's used to disguise a Time Lord," the Doctor said carefully. "A Time Lord goes in, something else comes out. That device holds the data needed to return the Time Lord."

There was a sort of buzzing in Donna's head, as though a bell was sounding in the far distance and she could not quite process what was being said.

"Disguise?" she asked. "You mean it's a way to change your appearance?"

"It changes everything about them," Martha said. "Down to the molecular level, maybe even deeper."

"DNA and everything?"

"Particularly DNA," the Doctor said. "I know that we look human, but under the skin we're as different from you as you are from fish."

"You've got two hearts," Donna said vaguely. "I know."

"Two hearts, different blood, DNA that looks nothing like human DNA," the Doctor said. "Nothing like the DNA of any other species out there in the universe, actually. It's what makes us Time Lords, in part."

"Why would you need to disguise yourselves like that?" Donna asked.

The Doctor shrugged. "It used to be used if we needed to blend with a society totally for a long period of time."'

"We used it to hide the Doctor once," Martha said. "Time Lords are too unique. Where did you get that?"

"I don't know," Donna said. "I've already been through this with the Doctor. It's always been around."

Martha and the Doctor exchanged another unreadable look.

"Are you sure it's hers?" Martha asked.

"It must be," the Doctor said.

"Would you two stop talking about me?" Donna demanded. "I'm not deaf, you know."

"If that thing is yours," Martha said, "then you must be a Time Lord."

Somewhere in Donna's mind she had already worked that out, but she had been trying to ignore it and pretend that there had to be some mistake. It was impossible, surely.

"You're having a laugh, right?" Donna said. "Have fun with the stupid human and all that. Well, it's not working and it's not funny. I'd remember if I was a Time Lord."

"The chameleon arc replaces your memories," the Doctor said. "It chooses somewhere in time to put you, supplies all the memories and makes sure that everything in that time is set up so that you can be inserted seamlessly. Nothing remains, not one molecule or memory that could be traced back to your true self."

"Nothing except this," Donna said dully, picking up the fobwatch.

"It has a sort of compulsion on it," Martha said. "You won't throw it away but you won't think about it, either."

"How do you get the Time Lord out?" Donna asked.

"You open it," the Doctor said.

That serious, horrible look was back and Martha looked almost as bad.

"It's that simple?" Donna asked.

"It's that simple," the Doctor agreed.

"What's the catch?" Donna asked.

There was always a catch and Donna was having trouble processing anything right now, much less working through the logic of all this.

"We don't know who you were," the Doctor said simply.

"But this arc thingy can't change people that much," Donna said faintly. "That can't be possible."

"Oh, it can," Martha said. "It really can."

---

There was a playground down the street and around the corner from her old house. Donna had been allowed to ride her bike there on her own as soon as she turned eight and Danny Maguire had been her first kiss under the swings there when she was ten. It was where she went when she needed to think because nobody let their kids go off on their own like that anymore and Donna found the sight of tiny children tumbling around on the new safe matting while their parents watched from benches oddly soothing. She hated kids when they ran around shopping centres, knocking people over, and she had got one family banned from a restaurant because their brats would not stop screaming. Why she found little children playing so restful was a mystery. The biological clock that everyone told her was sure to start never ticked when she was there. Perhaps it was the idea of all that life and potential that helped her to think.

Or perhaps humans were contrary by nature.

She wanted to forget about that conversation in the TARDIS, wipe it from her mind and pretend that it had never happened. It had occurred to her that maybe the watch belonged to someone else, perhaps an old great aunt who had died before she got around to opening it, except she would remember something like that because her mum loved telling her where everything in the house had been inherited from. All those thoughts that had been so slow in processing when she was sitting there with the Doctor and Martha were now working, reasoning things out that she wished could be wrong.

If the watch was hers and she was a Time Lord, then Wilf was not her granddad and her parents were not hers. She had been inserted into their lives one day and they had never known. That thought cut so deeply that Donna felt tears trickle down her cheeks. She took deep breaths and bit a knuckle to keep herself from crying properly.

Donna felt rather than saw someone sitting down on the bench beside her. Whoever it was stayed silent for a while and Donna knew that it had to be Martha rather than the Doctor. He would try to talk about it, or tell her that nothing had changed.

"What was he like?" she asked eventually. "The Doctor, when he used the chameleon arc, I mean."

"He was different," Martha said. "And he was the same. It's hard to explain. He still wanted to do the right thing and couldn't resist butting into a mystery, but he taught children to use machine guns and he fell in love."

"He taught you to fight," Donna said quietly. "How's that different?"

"I had to learn," Martha said. "It wasn't something he could avoid teaching me, I know that now. If I'd stayed here...but I didn't."

"He didn't remember any of it?"

"Not consciously, no," Martha said. "He dreamed about it all, though. I don't think the chameleon arc can wipe someone's mind completely, no matter what it's supposed to do."

"I might be the same, then, when I'm a Time Lord," Donna said. "Not exactly the same, but I wouldn't be completely different, the important stuff would still be me."

There was silence and Donna finally turned her head to look at Martha.

"What?" she asked.

"We found another Time Lord, once," Martha said slowly. "There was no way to know who he had been, before, but he had a fobwatch and he opened it. He was a sweet, gentle man before."

"And?" Donna prompted when Martha stayed silent for too long.

"The Doctor called him the Master," Martha said. "He told me once that not all Time Lords were good, just like not all humans are good or not all aliens are bad. They were friends, a long time ago, but something went wrong with him. He was insane."

Donna's stomach lurched.

"He took our TARDIS," Martha continued, "came to Earth and turned it into a terrible place. He tortured people – my family – and made humans into slaves and then he tried to destroy everything just because he could."

"I don't remember-"

"Nobody does," Martha said. "Just me, my family, the Doctor – the people who were there when it ended. He did something to time and the entire year was wiped out."

"Is that why the Doctor looked so angry?" Donna asked.

"We don't know who you were," Martha said. "There's no way to find out unless you open that watch."

"So I could be me or I could be some kind of homicidal maniac," Donna said unsteadily. "Great."

Martha reached into her coat pocket and pulled something out, opening her hand to reveal the fobwatch.

"He wants you to have it," Martha said.

"What should I do?" Donna asked.

"I think that's up to you," Martha said. "We can't decide for you."

"Would you stop me?" Donna asked. "If I...you know."

Martha looked grim. "Oh, yes."

---

The baby screamed and Shariana clung to her, holding the tiny body to her chest with aching arms.

"No!" she cried. "I won't let you kill my baby!"

Kainel shook his head. "I won't kill her, I promise. But we must hide her."

"How do you know that she'll survive the chameleon arch?" Shariana asked desperately.

"I don't," Kainel said. "But there's a chance. If we take her to Arkadia she'll die for certain. We must take the chance."

"I can't lose her," Shariana said. "I can't."

"Do you think I can?" Kainel's voice broke on the last word and tears ran down his face. "It's the only chance she has. Dariethen will let us stop on Earth for a few minutes and you know that our biology is unique in this universe. There is nowhere we can hide her unless we do this."

"I don't think I can do this," Shariana said.

"You won't have to," Kainel said. "I will."

---

Donna walked around her old neighbourhood for a long time, pulling out all the old memories and wondering which ones were hers and which ones had been created for her. None of it made any sense. How could something – even an alien device – implant memories into so many people?

When had she arrived on Earth?

Deep thought had never been Donna's thing before she met the Doctor. Now she was thinking and there were so many questions in her mind that she did not know where to start.

As the afternoon drew on and it became chillier, Donna's feet took her unconsciously to her house. She still thought of it that way, even though her future was with the Doctor and the TARDIS was her home. The driveway was empty and Donna was relieved that her mum would be out. As much as she loved Sylvia, their conversations were never easy and it was not her that Donna had come to see.

"Donna, love," Wilf said as he opened the door.

"Hi Gramps," Donna said, and then she burst into tears and threw herself at him.

It took a while to calm herself and Wilf just held her and gave her Kleenex until she was down to shuddering sobs rather than tears. Then he made them both a strong cup of tea with lots of milk and sugar and got the chocolate digestives out of the flour jar where Sylvia had tried to hide them.

"What's wrong, love?" he asked after they had sat in silence for a while.

Donna dunked the biscuit in her tea, trying to get it just the right degree of soggy without having chocolate-y digestive-y bits falling off to lurk in the bottom.

"I don't know," she said eventually.

It was, surprisingly, the truth. There were so many things that were wrong and none of them were things she could talk to Wilf about yet. Perhaps she would never be able to talk to him about them. How could she tell him that she might not be his granddaughter?

Her mind shied away from that thought and instead she found herself asking him, "Gramps, do you remember when I was born?"

Wilf laughed. "Do I remember? Of course I remember!"

Donna smiled weakly. "Oh."

"Didn't your mother ever tell you?" Wilf asked and then continued, "No, she probably didn't. I don't think she remembers much of it."

"What happened?"

Wilf sat back with his third digestive forgotten on the coffee table. "I was waiting outside with your father – it's what we did then – so we didn't get to see much. It took too long and then a nurse came running out with you in one of those incubator things. Your dad was going to follow her but they said your mum was bleeding and they couldn't stop it. I went with you and he stayed with her."

"I had no idea," Donna said softly.

"The doctors said you probably wouldn't survive the night," Wilf said. There were tears in his eyes. "You were tiny and pale – bright red hair already – and I could hardly see whether you were breathing. I sat with you all night, I didn't want you to die alone, but I fell asleep. The next thing I knew, you were waking up the entire ward with your screaming."

"Why didn't Mum tell me?" Donna asked.

"I don't know," Wilf said. "She doesn't like to talk about it."

"My mum? Not like to talk?" Donna said.

Wilf grinned at her. "You know your mum. And speaking of the devil..."

It took Donna an hour to escape the house because Sylvia wanted to show her the new tops that she had bought and spend a while criticising Donna's directionless life. She eventually managed it by making up a dinner date and hurrying back to the TARDIS, remembering that she did not want to see the Doctor three seconds after she opened the doors.

Martha was still there and they were both sitting by the TARDIS console surrounded by multi-hued papers.

"You're back!" Martha said, looking up. "Doctor, she's back. I told you she'd be back."

"You thought I'd leave?" Donna said.

The Doctor shrugged and Martha rolled her eyes. "Of course he thought you'd leave."

"Oh." Donna was not quite sure how to take that. "Do you want me back?"

The Doctor looked at her very seriously. "Do you want to be here?"

"Yes," Donna said without hesitation.

"Good," the Doctor said, breaking into a wide grin. "Now, help us to sort this lot out."

The papers turned out to be files from Sigma Research. Lots of files, possibly hundreds, and after surveying the stacks and piles for a minute Donna sighed.

"How did you get these?" she asked as she started to pick things up and assign categories and piles to them.

All those years as a temp had frequently included file clerk jobs and she was an expert at working out systems for seemingly random information.

The Doctor grinned. "Martha was brilliant."

Martha rolled her eyes and held up an ID. "I asked. People get oddly cooperative when the tax man knocks on their door."

Donna laughed and it felt good to laugh. "Sneaky."

"Yeah, cooperative in giving you stuff but not in organising it for you," Martha said. "They just printed it and dumped it all into unlabelled boxes."

"I temped for the Inland Revenue once," Donna said as she separated out HR sick forms from corporate revenue statements. "It's what companies do when they're trying to slow you down. Instead of just refusing access, they give you so much paperwork that it takes you weeks to sort through it all and work out what is happening. By the time you know that important bit are missing, the stuff has gone to the incinerator and the CEO is in Rio. What are we looking for?"

"We'll know it when we find it," the Doctor said vaguely, hesitating before adding his handful of pages to the tax pile.

"I looked at their last annual report," Martha said. "They're doing OK, but their cashflow is tight. Where are they getting the money from to pay all these physicists and buy their equipment? If we can trace the money, maybe we can work out why they're experimenting with time travel."

"Where would aliens get money from?" Donna asked, nodding towards the Doctor. "He never has any."

"Good question," Martha said.

The Doctor looked up with a slightly befuddled expression. "What?"

Martha and Donna laughed, their mutual exasperation with the Doctor uniting them. It felt good to just forget about the fobwatch and everything it implied for a few hours. They worked together for hours, sorting through the papers and organising them under Donna's experienced eye. Martha somehow managed to get pizza delivered to the TARDIS without confusing the delivery guy and Donna made pots of tea every time they started to feel tired. It was tedious work, but became more absorbing as a picture slowly started to emerge and none of them were willing to take a break and possibly miss something. Finally Donna put a memo onto the HR stack and reached for the next file, only to realise that everything was now neatly organised around them. Martha was studying the contents of a brown cardboard folder intently and the Doctor was fiddling with a device that flashed little blue lights every few seconds.

"Are we done?" Donna asked, surprised to find that her voice was hoarse and sore. "Is that it?"

Martha had to clear her throat a couple of times before she spoke. "I think so."

"Oh." Donna checked her watch. "It's almost morning."

"I'm not sure that I can move anymore," Martha said.

"I'm not sure that I can see anymore," Donna said.

The Doctor looked up, annoyingly fresh and bright. "So what have we learned?"

That was when all the alarms in the TARDIS went off, the Cloister Bell tolling its deep, resonant peel and the lights dimming and reddening. The Doctor sprang up, Martha and Donna only a beat behind, all weariness forgotten as they ran around the console flicking switches and holding down levers at the Doctor's direction.

"I thought you said that you'd delayed them!" Donna yelled.

"They must be further along than I thought," the Doctor said. "Press the red one, no, the other red one. Maybe they had spare parts."

Martha was almost spread-eagled on the console, trying to hold two levers in place while the Doctor tapped a sequence into a keypad just above her head.

"Can they break into the Vortex?" she asked.

The Doctor huffed and ran a hand through his hair, leaving it standing on end even more than normal. "That's what I'm trying to stop."

Then he ran to the other side of the console, set a dial spinning and pulled the monitor towards him.

"They're almost in," he cried and began typing furiously at the keyboard. "No...no...Donna, the mallet."

The mallet had slid under the console and was resting against its base.

"Here," she said, holding it out.

"Nearly...nearly..." the Doctor said, continuing to type. "When I say now, hit the green panel under the console."

"What?" Donna asked.

"Donna!"

"Alright, alright," she said, bending down and locating a small green panel just under the edge of the console. "How hard?"

"As hard as you like," the Doctor said. "Do it...wait...now."

Donna hefted the mallet and hit the panel as hard as she could despite the awkward angle and all hell broke loose.

The grinding sound of dematerialisation echoed through the TARDIS, loud despite all the klaxons and bells, and the central column of the console began to move. The TARDIS lurched, sending Donna sprawling on the metal floor and knocking all their careful stacks of paper into a mess.

"What's happening?" Martha shouted.

The Doctor did not reply, busy holding onto the console with one hand while he continued typing desperately on the keyboard. The TARDIS almost seemed to do a somersault and Donna slid across the floor to impact painfully against the railings around the platform. Martha slid up the console, her head smacking into the central column as her feet left the ground. Miraculously she kept a grip on the levers but then the TARDIS righted itself and she was left suspended there. The grinding noise became intermittent, as though the engines were stuttering, and Donna smelled something burning just before sparks erupted next to the Doctor.

"Doctor!" Donna yelled. "Oi, Timeboy!"

His concentration did not break but the TARDIS began to shudder as though she was in the middle of an earthquake. Martha started to slide down the console and Donna scrambled across the floor to catch her around the legs and steady her, just before her fingers slid from the levers. Donna stood shakily and wrapped an arm around Martha's waist, holding her up as the TARDIS lurched again. She managed to grab the left-hand lever a moment before Martha lost her grip on it and somehow they both stayed upright.

"One more minute," the Doctor said. "Hold on!"

"We are bloody well holding on!" Donna shouted. "What the hell are you doing?"

"There!" the Doctor shouted triumphantly. "Got it!"

Abruptly everything stopped. The light in the central column went out, the alarms ceased, the TARDIS engines fell silent and everything became still. The quiet was so absolute that Donna's ears rang.

"It's over?" Martha asked vaguely.

It took Donna a minute to work out how to move her arms and release Martha from her tight grip. She felt battered and bruised and there was a sharp pain over her ribs as she slowly stepped back and lowered her arms.

"What was that?" Donna asked.

"They almost did it," the Doctor said soberly. "I used the TARDIS to block them."

"You used the TARDIS as a battering ram?" Donna asked incredulously.

"Well, more like a bottle stop, really," the Doctor said, walking slowly round the console.

"What happens if they try again?" Martha asked.

"I don't know," the Doctor said.

They were silent for a moment and then Donna noticed the blood that was slowly trickling along Martha's hairline.

"You're hurt," she said, tipping Martha's chin up gently with a finger. "You should get that looked at."

"I'm a doctor," Martha said with a faint grin. "It's fine."

"Yeah, and I'm the Queen of Sheba," Donna said with a snort. "Come on, you can tell me what to do."

They left the Doctor in the console room looking unhappily at the console and Donna took Martha to her room. There was probably a sick bay somewhere in the TARDIS, but she had not found it yet and she was not sure that she wanted to get too far into the ship right now. She had a first aid kit under the bed - it was there when she arrived - and Martha directed her to use the disinfectant swabs and tape up the small cut on her forehead.

"Are you alright?" Martha asked, resting a hand lightly on Donna's wrist as she fussed with the placement of the tiny pieces of tape.

"Yeah, I'm fine," Donna said quickly.

"Hmm," Martha said.

"What about you?" Donna asked, peering into Martha's eyes to see whether they looked right.

"Maybe a mild concussion," Martha said with fake cheer. "I'll be fine, thank you. Did you find anything?"

They spent a while comparing notes and when they returned to the console room the stacks of paper had been neatly placed into boxes and the Doctor was under the console with wires dangling around him and the sonic screwdriver between his teeth.

"Doctor?" Donna said.

"Hurgh?" the Doctor muttered.

"Is she alright?" Martha asked.

The Doctor stuffed some wires into an open panel and they all tumbled out again. He grunted irritably and rolled out, bouncing to his feet with all his usual energy.

"Just need to do a few repairs," he said. "Nothing too bad."

"Can we use her to block the Vortex again?" Martha asked.

"Ah, well, probably not," the Doctor said. "A few things burned out."

"So we need to stop them before they can try again," Donna said.

"Yes, yes we do," the Doctor said. "What do we know?"

Martha glanced at Donna. "About six months ago there was a cash injection into the company. They were struggling and it looks like Professor McGlaughlin had taken a leave of absence. There was a Doctor Kerr signing things for most of the year before that. Then suddenly McGlaughlin came back and there was a huge injection of cash, enough to pay for some major upgrades to their labs and the extra staff."

"Most of them are listed as contractors," Donna said. "On an unspecified project that has no sick time and no overtime. That's weird."

"Where did the cash come from?" the Doctor asked.

"That's one of the strange things - the cash was just there," Martha said. "We couldn't trace it. One board meeting they were debating how to pay staff salaries next week and the next day it was there. It's as though someone just handed them a couple of million pounds in a suitcase."

"Or in precious metals, perhaps," the Doctor said. "Your aliens could have had it with them when they crashed. What's valuable here is common-place in other galaxies. The better question is why would they be investing in an Earth company?"

"Professor McGlaughlin's house is two miles from the crash site," Martha said. "They might have stumbled on him accidentally."

"They needed a way home," Donna said. "Their ship was damaged beyond repair and they couldn't expect to stay hidden so they offered McGlaughlin something if he would help them."

"The Professor didn't strike me as the kind of man who is solely motivated by money," the Doctor said.

"Er, didn't you notice the Armani suit?" Donna asked.

"He's a scientist," the Doctor said. "That's his primary motivation."

"Knowledge," Martha said. "Technology. They need a way home, he gets to learn everything they can tell him. You said that he had found a way to predict antigenic shift?"

The Doctor nodded. "I thought it was a bit advanced for a company his size."

"So they bribed him with knowledge," Donna said, "and he's helping them to build a ship to get home."

"What if it's not a ship?" Martha said. "What if they're trying to use the Vortex to get home?"

The Doctor frowned. "None of the races in the Bedruga Cluster have experimented with it. Why would they be trying on a primitive planet like Earth when they could just build a ship?"

"Perhaps they can't build a ship," Martha said. "Perhaps Earth doesn't have the right elements or something."

The Doctor's face lit up. "Of course! Their drive technology. Earth can't produce the right components so they're adapting."

"So what do we do?" Donna asked. "Can UNIT shut down the lab?"

"You said that McGlaughlin's house is near the crash site?" the Doctor asked sharply.

"Yes," Martha said. "Why?"

The Doctor pulled her over to the monitor and began typing again on the keyboard. Donna instinctively grabbed for the railings but the TARDIS stayed silent. Instead a map appeared on the monitor with a small spot blinking.

"There?" the Doctor asked.

Martha nodded.

"That's where the signal came from," the Doctor said. "I assumed that they had moved the lab to stop us sabotaging it again. Perhaps they have another lab in his house?"

"We could shut down their labs," Martha said, "but we need to make sure that we get McGlaughlin and his friends. Otherwise they'll be back in a few months. We need to stop them for good."

"How do we do that?" Donna asked.

"I have an idea," Martha said.

---

Privately Donna thought that Martha's idea was probably worse than her Brigadier's idea, but it had the virtue of being quick to organise and giving them some hope of getting out alive should the aliens prove reluctant to be captured. Or it would probably work if the Doctor did not annoy the aliens too much.

Donna had a sinking feeling about the whole thing, but it was too late to do anything about it because the green army van they were all travelling in slowed to a halt. The road on either side was lined with trees, the kind that promised a nice dense forest rather than a tree-lined avenue close to a house.

"How far is it?" she asked as she jumped down from the truck.

"About a mile," Martha said.

She was dressed in sensible black army fatigues with sturdy boots. Donna's long purple coat and comfortable trainers were as close as the TARDIS wardrobe ever seemed to get to sensible clothes for running for your life in.

"You'll be ready?" Martha asked the UNIT captain who was still in the truck.

The man nodded. "Waiting on your signal, ma'am."

The forest was green and pretty, filled with bird song and odd rustles and ferns that caught at Donna's legs as she walked. She had always sort of liked nature, when it was nicely contained in gardens and parks with neat little paths that she could walk along without getting caught on brambles. Chiswick did not have much in the way of forests and babbling brooks, but they looked nice on TV. Donna had sometimes daydreamed as a kid of going to the country on holiday, but her mum preferred Bournemouth and sitting on the beach when Donna was really little and then there had been Tenerife when she was a teenager.

Remembering that all of that could be a lie cut Donna like a knife, but she firmed her shoulders and marched on because she would not allow herself to be the woman who collapsed when the world needed saving. She caught the Doctor looking at her with a worried expression a couple of times and the fobwatch in her pocket slapped against her leg sometimes as a reminder. It was hard to stop thinking about it with those constant reminders.

Who had she been before?

Why had she chosen to use the chameleon thing and what was she hiding from?

Martha jogged along quickly and they arrived at McGlaughlin's house sooner than Donna had expected.

They all crouched behind a holly bush and peered at it through the prickly leaves. The lawn was beautifully manicured without a single bit of cover. The driveway was covered with gravel - the pretty multicoloured stuff, Donna noted absently - that would crunch as soon as anyone set a toe on it and the front of the house was covered with climbing roses. None of it screamed 'scientist' or 'secret lair'. In fact, it all looked rather like the comfortable house of a country gentleman rather than the hideout of a mad scientist.

"How do we get over there?" Donna whispered.

"Quickly," Martha said, just before she stood, moved around the holly bush and sprinted for the side of the house.

There was no reaction, no alarms or dogs, so Donna exchanged a quick looked with the Doctor and ran for it. He overtook her a few feet from the red brick wall and they leaned against it, panting and laughing.

"Now what?" Donna asked when she caught her breath.

"Now we get in," Martha said.

Donna gave Martha her best "d'uh" look and asked, "And how do we do that?"

She had to whisper so she could not put the right amount of sarcasm into it, but Martha rolled her eyes so Donna thought she had got the point across.

It seemed that Martha had planned the break-in better than Donna had thought. She led them to a door in the grass, just near the corner with the front of the house, that had been painted green to blend in but had no rust on the hinges. Two seconds with the Doctor's sonic screwdriver had it open and the Doctor dropped through it lightly before either woman could object.

A moment later his voice floated out. "What are you waiting for?"

They both slid in quickly, Martha first and Donna following, to find a short chute that dropped them into a damp cellar.

"Coal," Martha said quietly. "This place is two hundred years old."

The coal cellar's ceiling was low and it was obvious that nobody had bothered with it since the house had been converted to central heating. The musty, damp air caught in Donna's throat and she coughed into her sleeve. There were stairs nearby, wooden things that wobbled dangerously but did not give way even under the weight of three adults. The Doctor had to use the sonic screwdriver again on the door and he peeped through cautiously before they crept out. They emerged into a small hallway. To Donna's right, at the end of the hall, there was a door that was open just enough to see gleaming copper pots hanging on a wall. To her left the hall terminated in another door, this one the kind with a round window that swung in both directions, and there was a narrow stairway leading off the hall just beside it.

"Where?" Martha mouthed.

The Doctor fiddled with the screwdriver for a moment, swept it around and then nodded towards the stairs. They were steep uncarpeted things and Donna strongly suspected that this was once the servants' staircase. The walls were whitewashed and plain, no pictures or ornaments and the only light came from the small window on each landing. Oak doors led off each landing, to the main parts of the house probably, and they climbed three flights before finally reaching a narrow hallway that seemed to run along the back of the house. There was another staircase ending in a tiny door at the end and Donna grimaced as she realised that it led to the attics and that was they were going. At least it made a change from secret labs in the basement, she decided.

Martha put a hand on the Doctor's shoulder to stop him as he reached for the handle.

She lifted a radio to her lips and said quietly, "Eagle in place."

"Greyhound ready," came the quiet, crackly response.

"Bulldog ready," came another voice.

"Go," Martha whispered to the Doctor.

The stairs should have creaked - that was the way it went in films - but they were silent and the door had a well-oiled hinge. No dust marred the darkened wood and golden sunlight poured through large skylights in the roof. Donna was behind Martha and the Doctor so she did not immediately see the people and equipment. The area around the stairs was piled with boxes and tea chests labelled with neat, tiny handwriting that said things like "Sarah's dresses" and "Sarah's shoes". The labels were bright white with dark, pristine ink.

"Oh, dear, I'd really hoped you would be more original," the Doctor said loudly. "This is all very Hammer horror and you seemed so creative when we met in London."

Martha turned away and spoke quietly into her radio. "Go, go, go."

There was a scuffle at the far end of the attic and Donna pushed past the Doctor to see. Three men stood there, one holding up a small grey metal box while the other two froze, their eyes wide and frightened. It took a moment before Donna recognised Professor McGlaughlin with the box. His hair was dishevelled and he wore faded jeans under a grubby lab coat that might once have been white but was now an indeterminate shade of grey. A familiar piece of equipment stood next to him - the Vortex manipulator - and it emitted a low, intimidating buzz like it held a hive of angry bees. The air felt strange, electric and charged and Donna's skin felt too tight.

"You're too late," McGlaughlin declared in a feeble voice. "It's ready."

"Professor," the Doctor said sadly. "It's never too late. You can still stop it."

"You don't understand what this is!" McGlaughlin said.

"Oh, but I do," the Doctor said. "I think that I understand it better than you do."

McGlaughlin looked to the men beside him, doubt flickering for a moment on his face, and then he said, "Nobody on this planet can understand."

"Who said that I was from this planet?" the Doctor said.

The men beside McGlaughlin looked human at first glance. They were both slim and tall, with short brown hair and dark brown eyes. One wore a lab coat over smart trousers and the other wore jeans and a sports jacket, the kind of thing that always told Donna that a man was trying too hard to look trendy. It was hard to tell whether their pallor was natural or the result of too many hours shut in a house. If she had not known about the crashed ship, she would have assumed that they were human and not looked further for the tiny clues. They were there in the glint of metal on the back of the nearest man's neck and the way that their eyelids flicked up instead of down when they blinked.

"You said that you were alone," McGlaughlin said.

The one with the metal on his neck said, "We are. I don't know what he is."

"I don't know what you are, either," the Doctor said pleasantly. "I do know that your ship is from the Bedrusa Cluster but you're definitely not. From there, I mean."

"We are Sta'atil," the nearest man said. "I am Commander Bregal, this is Captain Sindil."

"Where is your planet?" the Doctor asked. "What are the galactic co-ordinates?"

The commander reeled off a string of numbers and letters that meant nothing to Donna but the light of comprehension suddenly dawned on the Doctor's face.

"You stole that ship," the Doctor said. "The ship you arrived on, you stole it and got yourself stored in the databanks for transit. That's why it doesn't look big enough to transport you. Somehow it crashed and you were rematerialized, but you couldn't fix the ship before the authorities arrived to investigate."

"Our original ship was damaged beyond repair and we were separated from our unit," Bregal said. "We captured another ship, but it was damaged and the escape pod did not have the range to return to our system so we crashed on this world."

"You've been trying to find a way home," the Doctor said. "All of this, it's been about getting home. Let me guess, Professor McGlaughlin agreed to help you in return for something that he needs."

Captain Sindil nodded stiffly. "Your assessment is correct."

"But why would you experiment with time travel?" the Doctor mused.

McGlaughlin snorted. "That was my price. I would provide the equipment they needed and they would create this machine for me."

A faint golden light was starting to surround the Vortex machine, so soft that it might have been the afternoon sunlight but Donna could see a shimmer to the light that was unnatural.

"You thought that you could use this machine to travel through space," the Doctor said sharply. "How far along is the research on your home world? And why do you have access to it?"

"Commander Bregal is a member of the science directorate," Sindil said. "It is his research which we have been trying to perfect."

"We have perfected it now," Bregal said. "This is the final test."

"You must stop your test," the Doctor said urgently. "What you're doing will work but you'll destroy everything."

"Impossible," Bregal said. "I have calculated perfectly. The wormhole will open to precisely the co-ordinates that the Professor has supplied."

"Uh, Doctor," Donna said nervously. "That thing is glowing."

"I can see that, Donna," the Doctor said without taking his eyes off the professor. "You need to shut the manipulator down."

"No!" McGlaughlin shouted. "We are so close!"

"Doctor, the lab is secure," Martha said, "and the house is surrounded."

"It doesn't matter," McGlaughin said. "In a few minutes none of it will matter."

"Where are you going?" the Doctor asked. "What is this all for?"

"I know," Donna said quietly.

All the pieces, all the clues, had been turning around in her mind and she felt as though they were suddenly slotting into place. The unexplained absence from the company and then his reappearance just around the time that the aliens – whatever they were – appeared. The boxes surrounding them.

"Who was she?" Donna asked. "Your wife? She died, didn't she, and you think that you can go back and stop it."

"She didn't need to die," McGlaughlin said. "I can stop it."

"No you can't," the Doctor said.

"I can," McGlaughin said. "I've thought it through most carefully. If we had found the cancer sooner, she could have been saved. I'll go back and send myself a letter. None of this needs to happen."

"If none of it happens," the Doctor said, "you won't be here, going back to send yourself a letter."

"Ah, but I will be," McGlaughlin said triumphantly. "I'll include instructions in the letter. These creatures will still crash and come to my home and I'll still help them to build the wormhole machine so that I can go back to warn myself again. The cycle will be complete."

"You won't be able to," the Doctor said. "It won't work."

"Who will stop me?"

"Time," the Doctor said. "You cannot change events like this, time has ways to clean up and stop you. Trust me, I've seen it happen."

"And why should I believe you?" McGlaughlin asked.

"I'm a Time Lord," the Doctor said. "Nobody knows more about this than I do."

It meant nothing to the professor, but Donna noticed that both the aliens seemed to grow paler at the Doctor's words. The glow from the machine was growing stronger, outshining the golden afternoon light and the buzzing was starting to make Donna's head ache.

"I thought your people were a myth," Sindil said. "All these years, we've heard stories but nobody had seen you."

The Doctor smiled, but it was an expression that didn't reach his eyes. "Oh, we're not a myth yet."

Bregal looked to the professor. "It's over, we must stop."

"No," McGlaughlin said. "We've come too far. What can he possibly do to stop us now?"

"There are stories of his people," Bregal said. "Stories that would be terrible even if they were only half true. We must shut the machine down, now."

"What will happen if it works?" Sindil asked nervously.

"Oh, terrible things," the Doctor said. "That machine will destroy everything if it works."

"The calculations..." Sindil protested.

"You don't know what you're doing!" the Doctor said. "Your machine isn't opening a wormhole; it's opening a hole in the Time Vortex. Nothing can survive that, nothing should survive that."

"Doctor," Donna said.

The machine was almost hidden now by the cloud of golden light surrounding it and the buzzing was becoming unbearable. Her hand crept into her pocket without conscious thought and she found the fobwatch warm beneath her fingers, almost vibrating with some terrible eagerness. For the first time since the Doctor had told her what it was, Donna desperately wanted to pull the watch out and open it. The thought almost made her sick and she realised that she had already made her decision about what to do. She wanted to remain Donna, stay herself and not become a part of whatever madness the life of a Time Lord would bring.

"Doctor!" Donna said more urgently. "I think the machine is doing something."

"You must shut it down," the Doctor said, stepping towards the professor.

"Never!" McGlaughlin shouted.

Everything after that moment became a blur in Donna's mind. The two aliens turned on the professor, struggling with him even as he tried to lurch for the machine. Donna ran towards the machine, not even aware that she had pulled out the fobwatch until there was a sharp pain in one finger. It had cut her and the red blood seemed to glitter in the strange light of the machine. The Doctor was just behind her with his sonic screwdriver extended and flashing.

Blue light arched from the screwdriver to the machine and the buzzing almost overwhelmed Donna. She put her hands over her ears in a vain attempt to shut the noise out and the fobwatch fell to the floor.

"Doctor!" Martha shouted.

Donna moaned and rocked, sliding to the floor as the metal behind her began to judder and scream. Blue and gold light mingled, strengthening and building until Donna was blinded and then everything in her head shattered.

She blacked out for a while, coming round with Martha's blurred face above her and a warm hand on her forehead.

"What happened?" Donna asked, her voice faint and croaky.

"You fainted," Martha said. "The Doctor shut that machine down, but it doesn't seem happy."

Donna winced as she turned her head. The Vortex manipulator was blackened but still vibrating, the buzzing noise now turned to angry metallic groaning. Sindil was scrabbling through some wooden debris: it looked like part of the roof had collapsed where he and the professor had been standing.

"Where's the Doctor?" Donna asked.

Sindil suddenly crowed with delight and pulled, dragging the Doctor to his feet as wood and tiles showered from him. The Doctor shook his head, dislodging dust and dirt, and then looked around.

"Bregal? Professor?" he asked.

Sindil shook his head.

"Right, time for a strategic exit, then," the Doctor said. "Donna?"

Donna rolled painfully to her knees and began searching the floor. "I can't go, not yet."

"Donna, there's no time," the Doctor said.

She continued searching; scrabbling under papers and shattered bits of roof as the machine's death throws grew louder above her. Then, miraculously, she felt smooth metal under her fingers and the warmth of the fobwatch sent relief coursing through her. Grabbing it, she stood up with Martha's helping hand and they followed the Doctor and Sindil downstairs.

This time they ran through the house without a care for who might hear them, only hoping to get to a door before the manipulator finally gave up. Sindil led the way, familiarity taking him without hesitation to the wide main stairs. Donna stumbled and almost fell as they flew down the stairs, but Martha caught her and they ran together faster than she had ever run before.

They collided with the locked front door and Sindil moaned his terror, but the Doctor had it open in a moment and then they were outside without a second to spare.

There was a loud, shuddering boom from above and moment later the house exploded. Donna felt herself fly through the air and then everything was blackness.

---

This time Donna woke up in the back of an ambulance with the Doctor looking down at her, his expression concerned through the mask of grey dust.

"How do you feel?" the Doctor asked.

"Like a house just fell on me, how do you think I feel?" Donna said irritably.

The truth was that, apart from the headache trying to drill its way through the back of her skull, she did not feel too bad. She was a bit bruised and achy, but nothing felt broken and she suspected that she was actually quite lucky.

"Good," the Doctor said, grinning properly now. "That is really, really good."

"How is everyone else?" Donna asked. "Martha-"

"Is fine," the Doctor finished. "She's directing the clean-up. There's rather a lot of it. Captain Sindil is answering some questions but I promised to drop him off at his home world when UNIT has finished. It's probably not a good idea to leave someone with his knowledge in their hands for too long."

"What if he tries again when he gets home?" Donna asked.

"Oh, I don't think we need to worry about that too much," the Doctor said cheerfully. "He's learned his lesson, I think."

"Oh," Donna said. "When do we need to leave?"

"We can probably take a day or two," the Doctor said. "You should really get that head of yours looked at properly."

Donna winced. "I'll be fine."

"Mm," was all that the Doctor said and then, "Did you find it?"

It took Donna a moment to realise what he was talking about and then she fished the fobwatch out of her pocket and held it up.

"Have you decided?" the Doctor asked.

Donna smiled at him. "Yeah. I think I'll leave things as they are for now. Why break a winning formula?"

---

"She looks kind," Shariana said, tracing her fingers lightly over the blonde woman on the monitor.

"I'm sure she is," Kainel said.

"Her daughter will die?" It was hard not hold her baby tighter as she discussed it. "We can definitely replace her?"

"The TARDIS is certain," Kainel said. "The chameleon arch even changed our baby's DNA. Nobody will ever know that we replaced the baby unless we survive Arkadia."

"She doesn't feel any different," Shariana said, stroking her daughter's fuzzy red hair. "She still feels like mine. Will this woman not feel the difference?"

"The baby had to be cut from her, as our baby was from you, so she has not seen her daughter yet," Kainel said. "There have been humans who did not know that their babies were replaced for years. This will work. Did she not survive the change? Is that not the best omen?"

"Yes," Shariana said. "I wish that we did not need this."

"You could stay with her," Kainel offered. "The chameleon arch would hide you as well."

"We must go to Arkadia," Shariana said sadly. "One life may make the difference. I cannot take that chance."

"Nor can I," Kainel said. "We may yet see her again, though."

---

They hung around Earth for a couple of days, letting Donna say goodbye to her family again and waiting for Martha to break Captain Sindil out of UNIT's secured facility. In the end, the Doctor had to carefully park the TARDIS inside the facility and escape with him after Martha left his cell door unlocked. It seemed a shame to let her get fired for freeing him when she was still so useful there.

The fobwatch might have stayed in Donna's pocket for the rest of her life if events had not interfered. That had been her intention and she had been absolutely certain that nothing would change her mind. Then they went to Davros' Crucible and the Doctor's aborted regeneration almost killed her.

The pain was more than she could bear, more than anyone could bear, and Donna almost threw up. The Doctor's hands on her shoulders did not give her strength; they seemed like the hands of a gaoler about to pull her towards a prison that she wanted to run away from.

"There's never been a human-Time Lord metacrisis before now," the Doctor said softly. "And you know why."

"Because there can't be," Donna said unhappily, the knowledge there without needing to think about it.

"You know what you need to do," the Doctor said.

"I want to stay," Donna said, almost crying through the pain in her head.

"I know," the Doctor said.

"I don't want to become her," Donna said desperately. "She isn't me. I'm the Doctor-Donna, not that other Donna. What if she's evil?"

The Doctor smiled through the tears running down his cheeks. "How could she be? She's you."

"Martha told me about Yana and the Master," Donna said. "What if-"

"Donna, you must open the fobwatch," the Doctor said. "Whatever you are, whoever you are, we can deal with it."

Donna moaned as the pain pulled at her. Bright flashes of light seemed to criss-cross her vision and she knew that she was out of time. The irony of a Time Lord with no time left made her giggle and she knew that she sounded completely mad.

"Promise me," Donna gasped. "Promise that you'll stop me."

"I promise," the Doctor said, not needing to ask why he might need to stop her.

Donna fumbled and almost dropped the fobwatch, but it seemed strangely reluctant to leave her fingers. The clasp almost seemed to leap open as her fingers brushed it and the lid of the watch flew open. Beautiful golden light drifted up and Donna smiled, the pain in her head seeming to die down as she watched the tendrils of light quest the air softly. It was a brief moment, just enough for Donna to sigh sadly, and then something seemed to latch onto her and turn everything inside out.

The first thing that Donna was aware of afterwards was the metallic grillwork of the floor of the TARDIS. There was a dent in it just before her nose and that was when she realised that she was lying on the floor. All the pain had gone and she felt curiously empty, nothing new that should not have been there and for a moment Donna panicked. Then the Doctor's foot appeared before her and she relaxed.

"Who are you?" the Doctor asked, his voice grave and deep.

She thought for a moment before saying, "Donna."

The Doctor crouched beside her. "Donna?"

Dizziness caught her as Donna sat up and for a moment the TARDIS wavered around her. Then it settled and Donna realised that she could hear the TARDIS now, just faintly in the back of her mind, and it was singing with joy.

"There's nobody else here," Donna said. "Just me."

The Doctor looked so puzzled that she laughed out loud.

"I'm fine, Doctor," Donna said. "I don't know what it did, but I'm fine now."

With the Doctor's help, Donna stood and leaned against the console. That dizziness was there again and now Donna realised that it was as though the world was spinning under her and she could finally feel it.

"What's going on?" Donna asked.

"I don't know," the Doctor said. "Can you remember anything new?"

Donna frowned. "Some of that time stuff is still here, but you're not in my head anymore. I think that I could still pilot this thing, though."

The Doctor took her hand and, before Donna could protest, he pricked her finger with a pin and touched the bloody fingertip to the TARDIS console.

"What the hell?" Donna asked. "Did I say you could steal my blood? No, I don't think so, Time Boy."

Her words slid off him like water and he frowned at something on the TARDIS monitor. After a moment Donna joined him and she realised that she could still read it, although it still did not make much sense.

"You're a Time Lord," the Doctor said slowly.

"Er, hello?" Donna said. "Didn't we establish that a few months ago?"

"But you don't remember anything," the Doctor said.

"Maybe it takes a while and I'll remember eventually," Donna said. "Did you remember who you were immediately?"

"Yes," the Doctor said. "Hmm, if I..."

He typed something into the keypad and his face cleared as he read the monitor.

"Donna," he said, "you're just Donna."

Donna shook her head. "What?"

The Doctor ran a hand through his hair. "Donna, there's nothing for you to remember. Your DNA isn't in the database but your mother's is, and your father's. She was carrying you just before the final battle at Arkadia. I don't know how she did it, but somehow she gave birth to you and she must have hidden you on Earth using the chameleon arc."

"I was a baby?" Donna asked.

"It shouldn't even have worked," the Doctor said. "The chameleon arc is designed for adults."

"My mum and dad?" Donna asked.

"Raised you," the Doctor said, answering the unspoken question. "Your biological mother's TARDIS probably picked out a family who were supposed to lose their baby – the original Donna Noble – and you were put in her place."

Something cold and unhappy released in Donna's throat and she swallowed a sob. Her mum and dad were her mum and dad in every way that counted. Gramps had raised her and loved her because she was Donna, not because a machine had invented memories of loving her.

"What was she called?" Donna asked. "My biological mother, I mean."

The Doctor looked at her with sad eyes. "Shariana. Her ship was destroyed in the first minutes of Arkadia."

"Oh," Donna said.

It was a pretty name, but it meant little to Donna and she could not make herself feel sadness for a woman she had never met, no matter what her DNA said.

"What does it mean?" Donna asked after a while.

"Mean?" the Doctor asked.

"What do I have to do now?"

The Doctor shrugged. "You can do whatever you want to do. There are some things that you should probably learn – time things – but I can't force you to do anything."

Donna frowned. "Can I stay here?"

"Of course!" the Doctor said quickly.

"Can you teach me the time stuff?" Donna asked.

"Absolutely," the Doctor said.

Donna hesitated. "Can I go home? Just to see them, let them know that I'm OK."

"We're already on our way," the Doctor said.

For a long time, Donna was quiet. It was not that she had nothing to say – she had more questions that she knew what to do with – but an idea had been growing and she needed to think about it properly before she said anything. She wondered whether this thoughtfulness was new but she knew deep down that it was something that had been growing ever since she first met the Doctor. Everything before had always been so easy and she had never thought how someone else would feel before she said things. Now she knew the power of a misplaced word and the Doctor looked unusually fragile.

"Doctor," Donna said. "We don't have to be the only Time Lords in the universe."

The Doctor suddenly looked pale and panicked.

"If Yana hid at the end of time and I was hidden on Earth, maybe there are other Time Lords out there," Donna continued. "Hidden Time Lords, waiting for someone to tell them what that strange little watch is that they've been carrying around all their lives. Perhaps there are dozens of little baby Time Lords out there that were hidden by their parents who never came home from the war."

The Doctor's face cleared and he beamed. "For a moment there, I thought..."

Donna looked at him for a moment and then shouted, "I am not bloody mating with you, you great git! What do you think I am?"

"Well, I..."

It took the Doctor most of the trip back to Earth to calm and placate Donna and she felt quite pleased with herself by the time she knocked on her mother's front door. He had promised a dozen things that she fully intended to collect on and all the yelling had made Donna feel quite cheerful.

Through the door, Donna heard Wilf shout, "Oh, that must be her! Donna?"

He opened the door and Donna hugged him tightly, breathing in his familiar scent and reflecting that he was home to her just as much as the TARDIS and nothing could ever change that.