A/N: Written as part of the 'Winter Companions' challenge over at the LJ community of the same name.

Specific spoilers for 'End of Time'; vague ones for the start of series five.


Perpetual Motion

"So...all of time and space. Everything that ever happened or ever will. Where do you wanna start?"

"How'd you find me?"

The thin stranger shrugged, sliding himself further along the bench.

"Wasn't that difficult, really. You're like- a great big constellation, all those fixed points, scattered across time. I just knew which one to look for."

"So I'm my own galaxy. Nice."

Jack's companion glanced across at him, elbows braced on his knees. "We came here, with Rose, once. After that party on Draxel IV. D'you remember?"

The memory was distant now, of another time and another life, but Jack smiled at it all the same. "When was that?"

"Er..." The Doctor checked his watch. "Next month."

"Okay."

There was a pause. Two joggers passed by in front of them, with a bemused backwards look at the mismatched couple; one in a long, military-style coat, the other sporting a bow tie. And, for some reason, elbow patches.

If Jack had been younger, he would probably have made a few approving comments about the length of jogging shorts in the 1970s.

In fact, when he thought about it, he was pretty sure that he had. Those days felt almost too long ago to believe in.

"You all right?"

Hazel eyes, older and more youthful than Jack had ever known them, were watching him anxiously. He returned the gaze.

"I'm always all right."

The Doctor groaned. "I had that one coming, didn't I?"

"Oh yeah." Jack held the smile in place until the Doctor looked away. Then he said: "Listen. The time in the bar, the last time I saw him- uh. Saw you..." The words seemed to stick in his throat, and he drew in another breath."You were dying, weren't you?"

His latest Doctor's head inclined, in the slightest of nods.

"Radiation poisoning."

Jack winced; he knew from bitter experience how much that must have hurt. "I'm sorry." Would have taken a while, too- which explained Ten's impromptu visit. "Was- anyone with you? I should have asked, I should've gone after you, I'm..."

"No, Jack. It was what I wanted. It was fine. I was fine- am fine, now. Really."

"Okay." Jack said again- feeling suddenly foolish, and far from indestructible. Another silence followed, a little more expectant than the first. In the distance, the city rumbled on.

"Alonso." The Doctor said abruptly, turning back round. "Tell me about him."

His old friend exhaled, passing a hand over his face. "Stayed with him about three years, 'till he got a job in this anti-grav joint, just over Earth. I – didn't fancy being tied down, yet."

"Was he nice?"

"Oh, yeah. Sweet kid. Great smile, great ass..." Jack grinned. "You know how to pick 'em." The grin faded, and a note of the familiar, weary sadness returned. "Seriously, though, thank you. I needed someone to keep me steady, back then." He stood up. "I should- probably get going. Work to do."

A spark of something- surprise, or realisation, it was hard to tell with this incarnation-, flashed in the Doctor's gaze.

"Right, so… you're not coming with me?"

Jack hesitated a moment, then shook his head. "I owe a favour to a couple friends of mine. Vinvocci research team, had a little trouble going on in the Berwyn mountains since January."

A muscle tightened in the Doctor's jaw; but if the name held special significance for him, he gave no other sign of it. "Mmm. Scared a few villagers, too."

"That's them. Anyway, they've gotta lie low a while 'till help gets there. Promised them I'd stick around for when the cavalry arrives, make sure they hear our end of the story."

"And then?"

"And then..." -Strange-familiar fingers brushed against Jack's wrist, as if to hold him back- "I'll call you."

Their hands pulled away. The Doctor cleared his throat. "All right. I'll see you. Soon. Ish. Promise."

"Yeah, I'll..." Jack trailed off, as the import of these last words finally sunk in. "'Ish'?"

A crooked half-smile tugged at the Doctor's mouth, and for a moment Jack thought he could see Ten again, daring and defiant and brokenly, exultantly proud. "Spoilers."

It was only later, as he bent once more over piles of Vinvocci paperwork, that Jack remembered that this was 1974, and he no longer had his mobile.

"Backwards or forwards in time. What's it going to be?"

There were, Rose was fast discovering, a few inconveniences about the nature of time travel.

For one thing, it played merry hell with your body clock, making it almost impossible to plan meals, or bedtimes, or even remember to sleep at all. For another, the sheer dizzying freedom of it left you open to either serious embarrassment or serious danger, since what was acceptable in one time or place was likely to get you lynched in another.

In any case, there was something rather undignified about being hopelessly drunk when it was only eight o' clock in the morning.

"Hello, ladies. Where're you headed for?"

"Jack, leave 'em alone."

"Sorry, Rose. But, you know, 1941, a girl turned out dressed like that, she'd be arrested. Not that I'm complaining, ladies."

The ladies in question fled, tugging down their checkered crop-tops as they went.

Rose gave an embarrassed giggle, which turned into a sigh as Jack seized her tightly around the waist.

"Ugh, geroff ...Doctor, maybe we should take him back to the TARDIS."

The Doctor shook his head, setting down their picnic hamper and pulling the sonic screwdriver from his jacket pocket.

"You asked for somewhere nice an' quiet, so I gave it to you. 'Sides, he'll be stone-cold sober in about five minutes. 51st century metabolisms, those things don't half work fast." He clapped an arm on Jack's shoulder. "All right, lad?" Jack beamed back, raising his right hand to his forehead in a sloppy salute.

"Aye-aye, sir. Doctor. Sir-Doctor. Did I ever tell you, Rose, 'bout that time Queen Elizabeth almost had me knighted?" He blinked, swayed. "Or beheaded. Not sure now. Anyway, someone had a really big sword."

Rose's eyes widened. "You met Queen Elizabeth? You mean, the First?"

"In the flesh. And very lovely she was too. 'Specially those ankles."

"Well, go on then. How'd you swing that?"

Jack winked. "Time Agency, Rosie. I know people. They know people. We get around."

"You buyin' any of this, Doctor?"

"Rose, you're asking the bloke who actually found El Dorado. The real one." He aimed the sonic screwdriver at their picnic thermos, which promptly started to sizzle. "Who wants tea?"

"Oh, now you're just showin' off. Right, Jack?"

Jack grinned, flashed them both a thumbs-up, and then pitched sideways onto Rose's lap. Rose frowned, looking worried.

"Is he gonna be okay?"

Any possible reply to the question was rapidly cut short, as Jack jerked back upright with a groan, pressing his palms to his eyelids.

"Agh. Liver's not going to thank me for this. Think I'll have that tea now, if you don't mind, Doctor."

He drank most of the thermos, while Rose boggled at them both, and silently bemoaned the lack of any sane, stable men in her life.

"Right then," the Doctor said, at last. "1974. Five years since the moon landing, two before Viking 1, and more sparkly eyeliner than you can shake a Q-tip at. Who wants to go first?"

"Look, sorry, I've got a bit of a-complex, life. Things don't always happen to me in quite the right order."

Despite being in possession of all the time in the Universe, the Doctor was terrible at keeping to schedules.

Dusk was beginning to fall. There was a crick in Jack's neck from the three hours spent lying on the bench, and the last passer-by had been almost an hour ago. It would be cold soon, too, but he didn't attempt to move, or even button his coat. In fact, he felt strangely comfortable; as if the return to previous haunts had reawakened other parts of his long-ago, lost lives. Waiting had been rather a talent of his, once.

Two years of helping the stranded Lucifer craft in its protracted legal battle with the rescue authorities had ended in ignominy last month, when he'd left his hotel in Bala to discover that the entire Vinvocci population had completed the deal overnight, and buggered off without him. It had taken every ounce of his willpower to resist calling Torchwood and demanding that they at least help him thumb a ride; he'd even gone so far as to pick up the phone, but the prospect of having to explain the nature of his dilemma to himself soon put a stop to the idea. Instead he'd spent the next fortnight patching up the Vinvoccis' discarded broadcaster, in the hope of sending out a stronger signal than the one produced by his own, battered manipulator. Damn thing was insured for five millennia, but Jack had passed the six-thousand mark some time back; only sentimentality, and a lingering sense of loyalty to the person he had been, had prevented him from seeking out a replacement.

"Jack."

A shiver that had nothing to do with the cool of the evening played across Jack's spine. He turned.

"So where'd you get a Vinvocci signal-frame from, anyway? Won't have those legalised on Earth for- ooh, 'nother two hundred years. Thought that Welsh lot should have cleared off by now..."

"Oh, God."

Ten frowned, hands in his coat pockets. "What? What is it?"

Jack checked his readings, stopped, double-checked them, and swallowed once, hard.

"I, ah- I think maybe your signal receiver is broken."

The Doctor sighed, running his fingers through his hair. "Ohh, again? Fixed her up only last week, duct tape usually does the trick for a bit longer than- agh." The last sentence ended in a winded grunt, as Jack flung both arms around him. After a moment the Doctor pulled back, cupping a hand against Jack's face.

"You're...you're old. No, I really mean it, you're ancient. What's going on? What happened?" He swallowed. "When are you?"

Jack kissed him on the mouth, and laughed, tired and sad and joyful.

"Spoilers."


Old friends, old friends,
Sat on their parkbench like bookends
A newspaper blown through the grass
Falls on the round toes
of the high shoes of the old friends

Old friends, winter companions, the old men
Lost in their overcoats, waiting for the sunset
The sounds of the city sifting through trees
Settle like dust on the shoulders of the old friends

~Bookends, Simon & Garfunkel~