A/N: Here we have the penultimate chapter! Tune in next week sometime for "We Who Remain!"

Chapter Five

13 September, 3:00pm

Martha Milligan was not a superstitious person. Unlike her sister Letitia—Tish for short, who checked her horoscope religiously, Martha had never been able to put her faith in the unknown. She needed something real, something concrete to which she could attach her beliefs. She needed something that could be proven, that left evidence of its existence. As she stood in Torchwood Tower, surrounded by the sick and the dying, she felt as if her existence had shifted drastically. She thought she understood the world—the laws of science, the guidance of reason and the fundamental possibility for good that existed in every person. As she looked around the room she realized how little she actually knew. Aliens. Alien illnesses. The universe was so much larger than she previously believed possible. Larger and more dangerous.

She pushed the gnawing thoughts out of her mind and brought her focus back to the patient in front of her. The worst part of this blasted sickness was the little they could do. Doctor Kane had isolated one anti-viral that was having more success than the others—it was still almost no success, but it was a start. Unfortunately most of the patients died before the medicine had a chance to help them. At least half expired within twenty-four hours of displaying symptoms. The bodies were piling up. Not literally, the government collected them before that was possible, but how many people had died in the Torchwood facility alone? How many across the city? The country? The world?

She shuddered. If this—whatever it was, escaped the confines of England it would ravish the population. They would not allow that to happen. The man in the dark suit, the one who was talking with Dr. Smith when she arrived the day before, had said as much. She believed him. He dressed like a businessman but he spoke like a soldier. There was something hard about him—something sharp and implacable. At the same time he was strangely familiar, like Rose had been before Martha connected the dots. Unlike Rose he made her nervous, but thankfully he seemed to be occupied in another part of the building, so she rarely saw him.

She did, however, see quite a lot of Dr. John Smith. He had returned shortly after the man in the dark suit sent him away despite the threats that had accompanied his departure. He was fully dressed this time, but he still looked as though he hadn't slept. He spoke to Martha occasionally, but mostly he sat next to Rose Tyler's bed and stared off into space.

Wearily, Martha began her rounds of the room again. As she drew closer to the Doctor she realized he was talking to someone. She paused, unsure if his words were directed at her, but he was looking at Rose.

"You'd listen to me talk for hours, remember? Fixing the TARDIS, wandering around on planets, staring up at the stars—I would point out a fleck of light and spin a fantastical tale." He smiled gently. "You liked the true ones best, you said. The made-up ones were good, but for some reason the true stories would reach out and touch you." He sighed and rubbed his thumb across the back of her hand. "You'll like this story, Rose, about a daft old man and his flying machine, and the girl who saved his life." He paused, thoughtful. "When you get right down to it, it's always about a girl. Well, maybe not for Jack, but you get the idea." Martha didn't understand half of what he was talking about, but she was intrigued. He spoke matter-of-factly, as if other planets and strange flying machines were ordinary. She blinked. Of course, in his world who's to say they weren't?

"There was this girl, you see." He began again. "And everyone thought she was perfectly ordinary. She worked at an ordinary shop, lived in an ordinary flat, and loved an ordinary boy, until an old, old man appeared and blew up that ordinary shop. He found her wandering around in the basement, about to be killed by shop-window dummies. He took her hand, and he said 'run.' And she did. She ran outside the shop and he told her to forget him, but she wouldn't. She kept digging, kept trying to find him until he found her again, quite by accident." He chuckled. "Remember Clive? Poor sod—he had that website with all my faces plastered on the internet. Right inconvenience that was. And then Mickey went and kept it going after the dummies got 'im! Anyway, back to the story. That ordinary girl saved his life, and to say 'thanks,' he took her with him when he left in his beautiful flying machine. Because all those people rushing about, filling their lives with work and sleep and chips couldn't see the strength and courage that radiated from her. He could, that daft old man. She burned in his vision and he was blinded by the light of her. He showed her the universe, and she showed him how to live—how to feel again. He was alone for so long—travelling through time and space and saving the world because he had nothing else left—a clockwork soldier. An empty man." He was silent for a while, lost in thought.

"So, when they ended up trapped by his oldest and deadliest enemy, the things that he had sacrificed his people and his planet to destroy, it seemed only right to send her home. He knew she would argue, that she would refuse to go, so he didn't give her the chance. He tricked her into his flying machine and he made it take her home, where she would be safe. He knew that he would die, but he didn't mind. He had seen a lot of this universe, that man. He'd seen and done terrible things, and maybe it was time for him to go. As long as she was all right, he could die content." The Doctor laughed. "He should have known better. He loved this girl from Earth for her spirit—her persistence and her courage and her compassion, and she loved him because she could see the good that he could not. Instead of accepting her fate, instead of living out her life while years in the future he died, she opened up his flying machine and took all the power of the universe into herself. The raw energy of space and time poured through her brain. And she came back. She took that power and she turned on his enemies—the last remnants of the Time War, the deadliest and most terrible war in the history of everything. She ended it to save the wandering soldier she loved. But there was a problem." His voice was rough and he paused to clear his throat. "The human body is far too fragile to safely contain the Vortex and he could see it bleeding through her skin, already beginning to burn her. He had two options: he could let her die, let her sacrifice her life for his, or he could save her. It would mean dying, in a fashion, but he could live with a new face as long as she was with him. So he kissed her—that daft old man, and took the power away from her. He channeled it back into his machine, but it was too late. He could feel himself changing, and he smiled, because she was safe. Rose Tyler, the girl who came back."

Martha began to move away. She was confused and interested, but embarrassed, as if she was intruding on something private, something sacred.

"I think it's a good story." The Doctor remarked again. "What do you think, Martha Jones?" He asked and turned to face her.

"I'm sorry." She stuttered. "I didn't mean to snoop or anything."

He waved her apology away with an amused expression on his face. "Never mind that. What do you think of the story?"

"Bit fantastic, isn't it? Time travel, that kind of space travel."

"You're standing in a building surrounded by people who specialize in dealing with aliens, after an alien ship crashed in the middle of London, and that story's fantastic?" He raised his eyebrows in disbelief. "Remind me not to tell you how it ends."

She looked confused. "I thought that was the ending."

He shook his head. "Oh, not by a long shot."

She rolled her eyes. "You don't know the meaning of 'impossible,' do you, Dr. Smith?"

"Now there you're wrong." The mocking smile was back, but it didn't seem to be directed at Martha. The Doctor stared at the wall as if he was remembering. "I know the meaning of 'impossible' all too well." He gestured at Rose. "She's the one who doesn't."

The icy metal of the handcuffs cut into her wrists. She sat silently in the chair, her arms bound behind her back. Her shoulders ached and she wished that they would let her go or just kill her all ready.

"You were discovered breaking into a secure UNIT facility." A short man with a neatly-trimmed beard tossed a file folder on the shiny metal table in front of her. "You will identify yourself and your employers."

They thought she was a spy. She almost laughed. "I want to speak to the Brigadier," she said, smothering the impulse to tell them exactly where she came from. The man raised an eyebrow.

"You are in no position to make demands."

She stared straight at him. He looked away like she knew he would. There was something about her direct gaze that made people nervous. Perhaps it was a bit of the Bad Wolf shining through, or the Void, or the fact that she really didn't care what they did to her.

"Go to the Brigadier, and tell him that the Doctor needs his help."

Hours passed, or maybe minutes. Rose couldn't tell. She dozed a bit, still bound to the chair, and dreamed. She realized that things were slipping away from her, little things, tiny details about the man she loved. How he took his tea, how his hand felt in hers, the sound of his voice. That last one hurt the most, because she loved his voice—the timbre, the excitement, the way it fell out from between his lips in a mad jumble of beautiful and occasionally unintelligible words. The 'click' of hard boot-heels on cement woke her. No, it was multiple 'clicks.' She opened her eyes. The man from before was back, and he had brought another with him. The second man was tall, with hair and a mustache that had been black at one time, but was now salt-and-pepper gray. He held himself stiffly erect, but Rose could see the intelligence in his eyes, and the curiosity. He pulled out the other chair from the cold metal table and sat down opposite her.

"What is your name?" His voice was brusque, but not harsh.

She shook her head. "Can't tell you. Too risky. One wrong word and the whole of causality will go to hell."

He frowned. "Where are you from?"

"You wouldn't believe me if I told you," she replied.

"Try me."

She leaned as far forward as the handcuffs would allow. "I'm from another universe, a parallel universe. Just like this one, almost identical actually, but it's not the right one. Neither of them. None of the ones I've seen are."

The Brigadier looked at her steadily.

She sighed. "Look, I really don't have time for this. Your goons took my stuff. In the right inside pocket of my jacket there was a pair of glasses. Get them, and look at me."

The first man rummaged around in her coat and pulled out the 3D glasses she had put in her pocket the last time she was with the Doctor. The Brigadier raised an eyebrow.

"Just do it," she said wearily. "If you believe I'm a lunatic after that then fine. Whatever. Can't say I haven't thought it myself."

He raised them to his eyes. He didn't gasp, but Rose saw his hands tighten on the glasses' frame. She knew what he saw: swirls of black particles moving around her, outlining and obscuring her. He pulled the glasses off and looked at her with piercing intensity.

"Who are you?" he asked again. "What are you?"

She cracked a tired smile. "Just a traveler, passing through."

14 September, 2:30pm
Jacqueline Andrea Suzette Tyler was crying. Pete held her and the Doctor was startled to note that tears were dripping down his face as well. His shoulders slumped and for the first time since the chaos began the Doctor realized how tired he looked—how old.

"What's wrong?" he asked Pete quietly.

"It's Tony." His voice was flat, devoid of emotion. "He's taken sick."

The Doctor's stomach plummeted. He hadn't thought—hadn't even considered, that Rose's little brother could die. But he and Rose both had been around the boy, and they were infected. "I'm sorry," he said quietly. "So sorry."

She rubbed her wrists, wincing. Raw welts, a reminder of her former captivity, stood out red and puffy against her pale skin. She rotated her shoulders, trying to work the soreness out of them. The ache persisted. She pulled her lips into a thin straight line and turned her focus back to the device in front of her.

"We have technicians that could help you," the Brigadier offered from behind her. She shook her head.
"You aren't supposed to have this kind of technology yet." she replied.

"And you are?" His tone conveyed his disbelief.

She snorted. "Not really. Not even supposed to be here. He said it was impossible." She frowned as she soldered a particularly tricky joint.

"And yet, here you are."

She looked up at him. "I don't believe in impossible."

16 September, 6:00am
The sick kept coming. Wave after wave—and the bodies kept leaving. Martha stood in the room, looking without seeing at the scene before her, noting mechanically the minutiae: a rumpled sheet on a momentarily empty bed, a pair of shoes tucked neatly out of the way, a book laying half-open, discarded. She hadn't slept, not well, anyway. How could she sleep when the world was ending all around her? Is this how Tom felt, standing in the middle of a refugee camp? Did he experience the same shift, from hopeful to doubting to despairing to tired, so tired.

"You mentioned the Doctor." The Brigadier watched her fasten the newly repaired Jump tracker to her wrist.

"Yeah," she replied, as noncommittal as she could. "I did. Only way to get you down here, and you're the only one who could get me what I needed to fix this thing."

"What is it?"

"Helps me jump."

He was silent for a moment. "Do you know about the Doctor from this universe? Is he coming back? He always flits in and out, but we haven't had a sighting of him in years."

Rose shook her head. "I'm sorry," she said, and she was. "He's dead."

"Dead." His voice was flat.

She drew in a deep breath. "There was this war, and he stopped it. But he didn't make it out in time, not in this universe."

"And he did in yours."

She looked away. "Yeah."

The Brigadier nodded. "I hope you find him."

"Me too." She punched in a few numbers on the Jump tracker, and she was gone—back into the Void.

17 September, 4:00pm
"How is she?" Martha's voice broke through the Doctor's contemplations. He glanced up at her, and then back to Rose.

"The fever's broken."

She smiled. "That's a good thing, yeah? Most of the patients who beat the fever survive." He nodded, but he still looked serious, almost angry. "What's wrong?" she asked.

The Doctor nodded to a bed a little ways away. A small boy was hooked up to an IV. A woman who looked remarkably like Rose sat in a chair beside him, and the man in the dark suit stood at the foot of the bed, staring at the wall. "That's her brother." The Doctor's voice was soft. "And her mother, and father—well, sort-of father. Inter-universal lives are almost as complicated as time-traveler's lives."

"How is he doing?" She chose to let the comment about other universes and time travel pass.

"Not well," the Doctor replied. "He's too young, even with the medicine. He isn't strong enough to beat it, unless—"

"Unless what?"

The Doctor leaned in very close. He had a strange look on his face, an intensity that seemed to burn into her. "Do you trust me, Martha Jones?" he asked, his eyes never leaving hers.

She blinked as echoes of a previous conversation danced in her mind. "Can I trust you, Martha Jones?" Rose had asked her that. "What is it with you people and ignoring the fact that I'm married!" she snapped, and held up her left hand so he could see the engagement ring and wedding band on her ring finger. "And what kind of a question is 'do you trust me?'" I barely know you; I met you less than a week ago!"

"I know." His eyes continued to bore into her. "But I need you to trust me. I need to you to believe me when I tell you certain things that—despite our surroundings—seem very strange and just a bit impossible."

"Something can't be 'a bit impossible,'" she replied. "It's possible or it's not."

"That's a matter of some debate." He leaned back. "The question stands: do you trust me?"

Martha chewed on her bottom lip as she stared at the Doctor. Every instinct she had was screaming at her, telling her this man was a nutter and possibly dangerous and definitely to be avoided, but if someone had told her a month ago that aliens were real she would have called them a nutter too. And there was something about Doctor John Smith, something that made her want to believe him. She sighed. "All right. I trust you."

He grinned. "That's the spirit! Nothing like a good, old-fashioned leap of faith! Now," his voice turned serious again. "First things first. My name isn't John Smith."

"Then what is it?"

"The Doctor."

Martha looked at him expectantly. "Doctor who?"

He frowned. "Just the Doctor."

She rolled her eyes. "Do you even have a degree?"

He looked hurt. "I have several! Some of them even from Earth, although I'm not sure they'd be valid in this universe—anyway. That's the next bit. Rose and I—and her Mum, for that matter, aren't from this universe. We weren't born on this Earth, well, I wasn't born on Earth at all-"

"Wouldn't that make you an alien?" Martha interrupted.

He nodded. "Yep!" and popped the 'p.'

"You're an alien." She didn't believe him.

"Mostly. Ninety-four percent, maybe, or ninety-three and a half which is just as good as ninety-four percent."

She shook her head. "You're barking."

"Martha." He leaned in again. "I'm serious, and I'm not mad. Well, maybe a little mad, but that's beside the point. There are millions of parallel universes out there. Rose and Jackie and I travelled to this universe. I was a time traveler and Rose travelled with me."

"How?"

"I have—had a ship. But I'm making a new one."

"Why are you telling me all this?" she asked.

He took a deep breath. "I can fix this. I can come up with a cure—I think."

"Well then do it!" She almost shouted. "How long have you known about it? Why haven't you done it yet?"

"I wasn't sure if I should," he responded. He ran his hand through his hair and began to pace in a tight circle. "It's too early!" he exclaimed. "My body hasn't adapted to this universe yet—if I could only see!" He put all of his frustration into the last word. "The timelines don't feel fixed, but I can't see them!"

"Now you've lost me." Martha folded her arms across her chest. "What are timelines? What are you on about?"

"I'm a Time Lord, Martha," he explained. "I can see Time, I can feel it: all the possibilities, moments that are in flux and moments that have to happen. But not yet, not in this universe. My body hasn't acclimated to my surroundings yet."

"How long would that take?" she asked quietly.

He stared at the ceiling, calculating rapidly in his head. "Three weeks, give or take a day."

"In three weeks Rose's brother will be dead, along with hundreds of people."

He nodded. "You see my problem. If I act now, I'm flying blind."

"What makes him so special? We've had loads of children come in and you never said anything about them?"
The Doctor studied Rose's sleeping face. "In our original universe, Pete Tyler died when Rose was six months old. It was just her and her Mum growing up. She dropped out of school, never took her A-levels so she could help pay Rent. They had a hard life, but they made the best of it. And now they finally have a chance to be happy—Jackie has Pete, and a little boy, and this happens. Worse—I caused it. Rose and I went into the space ship after it crashed. We weren't supposed to be there. We were supposed to be shopping, but we went ahead and got infected and spread that to Tony." A muscle in his jaw twitched. "After all the things this family has gone through for the sake of the universe—no," he corrected himself. "For my sake. They deserve to be happy."

"He could get better," Martha supplied.

The Doctor laughed. It was hollow, joyless. "If there's one thing I have learned in my very long life, Martha, it is that the universe is not kind."

She was silent for a moment. "Like I was asking earlier. Why are you telling me this?"

"I need you to choose." His voice was very soft. "I'm sorry, but I need you to choose. Should I do this or not?"

She gawked at him. "What?"

"Should I act, or should I let this pass?"

Anger bubbled up inside her. "You're passing the blame on to me. Why? Why can't you decide? Why are you trying to pin your actions on me? How am I supposed to know? You're the one who claims to be able to see Time! I'm just a person!"

"A very good friend once told me that I need someone who will stop me," he said quietly.

"And that's me." Her voice was flat. "I'm supposed to stop you. Why me? Why not Rose?"

"First, because I believe that you will. And second," his voice trailed off. He took a deep breath, and continued. "When I really, truly need to be stopped, Rose might not be there. She could be sick, or injured…or dead."

His words hung between them as Martha stared at the wall. The sheer weight of the responsibility associated with her answer settled over her like cement. Sporadic cases of the sickness had popped up in the surrounding countryside. So far the police had been successful in maintaining quarantine around the victims, but it only took one slip-up and the whole country would be at risk. But if she said yes and she was wrong, what were the repercussions? What did she know about meddling with Time? She sat very still for what seemed like hours, locked in battle within her mind. Finally she closed her eyes.

"Do it," she told him.

He nodded. "Thank you."