Jack sighed and tossed aside a scrap of Yana's tech - probably very clever, fantastic... brilliant, as this Doctor would say... but absolutely useless to him now. Across the room, Martha stepped delicately over the body of one of the Futurekind, paused for a moment like she was trying to decide whether she should at least move the body from its careless sprawl, close its eyes.

She didn't, just looked up, over at Jack. "I don't have a clue what I'm looking for. I'm a doctor... not really much good with technology."

"Dammit, Jack, I'm a doctor, not a rocket scientist," Jack muttered under his breath, glanced over at Martha with a faint smile. Martha gave him a flat look in return, and he rolled his eyes a little, still smiling, and shrugged a little. Worth a try, even if he didn't get a laugh out of her.

"To be honest, I don't either. None of this is anything I'm used to, and..." He paused to rap his wristband with two fingers. "I haven't been able to get this thing to work for years now."

"And what if we can't find something to get it to work now?"

He could see the fear in her eyes. She was good at not showing it, jaw set, chin lifted a little to look him in the eyes - if there was one thing travelling with the Doctor taught you... - but Jack knew where to look, and it was all there in her eyes, the lines of her body. He wished he could say something reassuring.

Martha turned away so he couldn't see her face, started searching through a few scraps on a table. "Are we stuck here?"

Jack watched her for a moment, all the words stuck in his throat. He could tell her the chances they'd die here. Or at least that she would. They seemed high. Or he could lie.

"We're going to find a way out of here."

Jack slammed the door shut, back pressed flat against it, while Martha lunged for Chantho's fallen body. Something thudded hard against the other side of the door, one of the Futurekind, and Jack shifted a little, using his whole body to brace the door closed. "Doctor, you'd better-"

Jack looked up just in time to see Yana step back into the TARDIS, start to close the door, but the Doctor lunged forward, blocked the door with his body. Jack's heart leapt into his throat, something rising in the back of his mind and just repeating no, no, no... He should be right there, in between the Doctor and Yana. He shouldn't let the Doctor step inside the TARDIS without him.

But he couldn't move from the door without the Futurekind getting in, and...

There was a scuffle Jack could only half see, the Doctor halfway through the TARDIS door already. The Doctor tripped forward, and kicked the door shut behind him. Jack shouldn't have been able to hear the lock click shut, but he could have sworn he did.

The door rattled again, harder. More of them out there, and how many could there be? "She's dead," Martha said, looking up from Chantho's body, and only then seemed to realize that both the Doctor and Yana were gone. "Doctor?"

"Whatever he's doing in there," Jack said with a grimace, "really wish he'd hurry up." Shouting outside the door. Shouting and almost animal snarling... They couldn't kill Jack, not for good, but they'd kill Martha, and what they could do to him...

What they could do to him suddenly seemed a lot less important as the sound of the TARDIS engines rose, a cycling groan that filled the air and thrummed in Jack's ears and here he was, standing in a far foreign place while that blue box containing his whole universe faded out of sight...

Last time, though, Martha wasn't there. Here and now, she lunges to her feet, lunges at the fading TARDIS, moves to pound on the door but it's already not real enough to actually touch. "Doctor! DOCTOR!"

It was gone. Jack stared for a moment, unable to breathe. Martha stared too, and then whipped around to face Jack. "What do we do?"

The door rattled so hard Jack's grip slipped a little, started to slide open. Jack growled, shoved it shut again, and glanced back over at Martha. "I don't know. But we better think of something fast."

"He left once before," Martha said, still carefully not looking at Jack. "Not long after we first started travelling together. He came back then. I guess that's obvious."

Jack glanced to Yana's computer system, the one the Doctor had been so enamored of. Maybe if he could find a way to patch that into his wristband he could augment the teleport just long enough to get them... anywhere but here... Shot in the dark. Probably pointless. Not that they had a lot of other options.

He looked back over at Martha, tried for a smile. "He might come back. Once he's finished with Yana... Could be we just have to wait a while, because he is really rubbish at precise navigation sometimes."

Martha looked at him finally, placing her back against the edge of a table, hands gripping the edge so hard her fingertips paled. Jack noticed, though he was sure she wished he didn't. "But he left you behind, before. Like you said, he just... took off."

Jack met her eyes for a long moment, and managed not to look away, much as he wanted to. "That was different." It's not easy, even just looking at you, Jack, 'cause you're wrong.

"So what? We sit here hoping he'll come back, hoping he hasn't gotten bored of us or found some reason to run away from us? What if-" Her voice faltered, for the first time, cracked a little, and Martha swallowed hard. "What if he's dead?"

And isn't this how it always was? Jack could play the hero, run in and shout commands and save the day. Shoot down the attackers, maybe die once or twice keeping everyone else alive, but when it came down to it, here he was, just as lost as everyone else without the Doctor.

"I don't know."

Searching through an empty base of any kind was always a nerve-wracking experience, especially when you'd never done it before. Even Jack could feel the back of his neck prickling. The shadows, the occasional odd noises, and Martha kept jumping, glancing over her shoulder like she expected one of the Futurekind to come creeping up behind her. Jack reached out to rest a hand on her shoulder, and she flinched before settling and smiling a little shakily up at him.

"I don't think there are any more of them out there," he said, and hoped that was reassuirng. If you ignored the whole "end of time" thing... He'd wondered what would happen to him, at the end of the universe, if he could never die. He just always assumed he'd have a few trillion years to come to terms with it.

Martha glanced down the hall that a few hours ago had been filled with people about to escape to Utopia. The press of bodies, the heat, the tension of hope and fear... Now, it was just cold and silent and dead, like the rest of the planet. "So it's just us, then? Just the two of us on the whole planet?"

"Looks like it."

He dropped his hand from her shoulder, moved a little distance down the hall and pulled open a door - without stepping through it, just in case it happened to be a door to nowhere again. Just a closet, with an assortment of machine parts, on top of which were a random collection of clothes, boots, a book here and there, what looked like a child's stuffed animal... Things discarded before the trip to Utopia. Or who knows, maybe it was a lost and found closet. Jack sighed, and glanced back to Martha.

"The two of us, and an empty base at the end of the universe. This isn't my usual idea of a first date, I promise."

She smirked a little at that, starting down the hall past him as he pushed the closet shut and dropped into step behind her. "Oh, I'm sure it could be worse." She paused a second. "I'm not sure how, but it could be."

"Well, you could be stuck at the end of the universe with someone much less charming than me," Jack suggested, and Martha laughed, the sound echoing down the hallway. Jack grinned, just to himself, as Martha was looking the other way. He could think of a few worse ways to face the end of the universe.

Somehow, being out on the surface of the empty planet was less unsettling than being inside the empty building. Strange - Jack would have thought the lack of stars would bother him. It had before, a little, but compared to empty buildings and echoes, he'd take the darkness.

Martha shivered. "Is it just me, or is it colder than it was before?"

Jack frowned a little, glanced out over the surface of the planet. As if he'd find an answer there. He hardly noticed cold anymore, but now that she mentioned it... He slung the coat off his shoulders and held it out to her. Martha studied him, like she was thinking about telling him to keep it, but after a moment she took it and pulled it on. It was so long on her that the edge of it dragged the ground, like a child playing dress-up.

"Why would the temperature change?" she asked, wrapping her arms around herself without bothering to fold back the sleeves of the coat, which hung past her fingertips. "It's not like they could have weather here. There's not even a sun!"

"There's barely an atmosphere," Jack said, following just behind her as she started up a steep incline, ready to catch her if she slipped. The top of this hill should provide a nice vantage point, provided there was anything to see. "Maybe the atmospheric shell is degrading. No reason to keep it up, now that every last human's off to Utopia. They could have pulled power from the heat trapped here, given the rocket a little extra boost..."

Martha stopped and turned to face him, worried, scared, but keeping it together pretty well for all of that. Jack wouldn't have expected any less from the Doctor's companion. "So if the atmospheric shell is degrading... we're just going to suffocate? Lose all the air?"

"Or freeze," Jack said, starting up the hill again, resting one hand at the small of Martha's back and pulling her gently with him. "I could be wrong, though. Maybe temperature fluctuations are normal here. It's the great heat death of the universe. All the energy's leaking out, fading away... But that's more the Doctor's area of expertise than mine, so maybe I'm wrong."

The air seemed thinner than before. Jack found himself drawing deeper breaths and still feeling a little winded, and he was not enough out of shape that a short climb up a hill would cause that. Maybe he'd been right about the atmospheric shell.

"What is your area of expertise, then?" she asked, glancing over at him, and Jack chuckled.

"Oh, that's a... long story." It was his default answer. Long story. Complicated. That sort of thing. It kept most people from asking too many questions - there was always the odd exception, like Gwen Cooper, but for the most part...

"So tell me," Martha said, her lips quirking into a tiny smile. "We've got all the time in the universe."

They reached the top of the hill - a gradual climb up on this side, a sharp drop on the other, and a view out across the rocky surface, a landscape all in shades of black and blue and gray. They could see the Conglomeration from here, and beyond that, miles and miles of rock and dirt, and past the horizon, nothing but empty space. The two of them stood there for a moment, both holding their breath at the sight. There was something about the emptiness that made Jack's chest ache. This had been somewhere, once. A real place, home to life, ancient civilizations, people... Nothing now. Just a rock, spinning in the void, no one to even remember it, unless those people did find their Utopia. Or unless he somehow lived on, the one man who couldn't die in a universe devoid of life of any kind.

He let out the breath. They sat down, huddled close against the cold, staring out into the darkness. And Jack did tell Martha, years and secrets and old, old pain. What could it hurt? They only had until the end of the universe.

"Martha?" She didn't answer for a moment, and Jack shifted a little, so that he could see her face - not easy, with her tucked under his arm, curled into a little ball while still huddled in his coat. They'd moved back into the silo, but it was still cold, getting harder to breathe - or at least, to breathe and actually get enough oxygen while doing so. The whole thing seemed to have powered down while they were out, and Jack hadn't been able to find the on switch, so they sat now in Yana's lab, leaning into each other, lit only by dim red emergency lighting placed here and there.

"Martha," he said again, a little louder, and she lifted her head.

"Hmm? What is it?"

"Just making sure you were alright. Hard to tell in this light." He felt a little ridiculous, just sitting here, waiting for something to happen. He should have learned a long time ago that waiting got you nowhere, not in a time and a place like this. But this wasn't a problem he could solve, nothing he could do to stop it. Broken vortex manipulator, no TARDIS, no way of escape. There was nothing left to do but wait.

"Still breathing," she said, though she sounded a little winded. "You don't have to worry about me."

"Well, I've got nothing else to worry about. I don't see why not." It was meant to come out light, flippant. It didn't quite make it.

Martha shifted a little, pressing a little closer to his side while tilting her chin up to look him in the eye. "There are worse ways to die, aren't there? Than this?"

Jack blinked down at her, and had to smile despite himself, and despite the topic of conversation. "Well, that was a nice slide into morbidness. I guess you're right, though. I can count a few ways I have died that are less pleasant..."

"I could have fallen into a living sun. Been eaten by a giant mutated... thing..."

"Oh, we're playing that game? There was this one time-"

"That's not fair," she protested, smacking him lightly in the chest. "You've actually died. More than once, even!"

"Well, you started it..." Jack answered with a grin, but let it go. He'd probably have had to dig into his days as a Time Agent to find a near-death that would beat "living sun" anyway. "I'm sorry, by the way," he said after a long silence. "For jumping on the TARDIS... throwing us back here..."

"Don't apologize. You didn't know, and if I were you... I don't know. I might have done the same thing." She sighed and closed her eyes for a moment, biting her lip, and when she opened her eyes it was with a sad little smile. "I never really told my mum... anything. I'll just disappear, and she'll never know. My dad, my brother and sister..."

Jack brushed her cheek with his fingers, and she gave him a flickering, reassuring smile that was clearly supposed to convince him she was fine, and really did no such thing. Jack's chest started aching again, in a faint, distant way, and he couldn't quite breathe, though it had nothing to do with the thinning air just then. He kissed her, then, which seemed the only logical thing to do at the moment, and Martha leaned toward him, Jack's fingers tracing lightly down her jawline, up the nape of her neck. Maybe it was the end of time, but they had time enough for this.

Almost time enough. A wind rose from out of nowhere, sending papers flying, ruffling their hair and clothes, and Jack and Martha broke apart, staring at the blue box that materialized with the cyclic roar they both knew so well. Jack had to wonder, for a moment, if he was imagining it, because he'd been through this story before, and he knew how it ended - he didn't come back, no matter how long you waited. But the door swung open, and the Doctor leaned out, hair and suit rumpled, what looked like dirt or soot smudged along one cheek, but alive and very much real.

He arched an eyebrow at the two of them, impatient and grinning all at once. "Well, come on then! We haven't got all day! Actually, we've got... uh... fifteen minutes, give or take, but I wouldn't push it."

They both stared a moment longer, with mixed disbelief and relief, until Martha lunged to her feet and raced across the room to the TARDIS, flinging her arms around the Doctor when she reached him and nearly knocking him over with the force of the hug. Jack followed just a half-step behind her, wrapping his arms around the both of them as he stepped out of the cold red emergency lighting of Yana's lab, into the warm green-gold humming interior of home.