He had to laugh.

It was a good joke, really.

Better than anything he'd ever pulled; better than anything they'd ever pulled off together, the four of them. No one else was laughing, but that was because they were dead, and that was funny too. All that blood, all that charred flesh, those horrified faces and Pettigrew's finger. Best punchline he'd ever seen.

If he couldn't stop soon, he was going to pop a rib.

Still, someone had to be told. Someone had to get it; practical jokes were no good, unless everyone understood it was done on purpose.

No, see, it was Peter all along. And I thought it was Remus, and now everybody thinks it was me. Four man gag; we haven't done that since Hogwarts; and Peter was usually the bait, then, or Remus. They wouldn't believe me or James. Did it all by himself, too. Little Peter. Who'd have guessed?

James. James would get it. This was just the sort of thing he'd appreciate. Never drop a plan that works, no matter how many times you've used it. That was his motto, and apparently Wormtail had been listening all those years, oh yes, and they'd all thought he was too weak to manage it on his own, that he'd crack if he had to carry too much of the responsibility.

But it was imperative that he avoid thinking about James just now. There were daggers down that path. Best to focus on something else. What, he hadn't decided yet. Up until a few minutes ago, it had been on killing Pettigrew, but that might have to wait. Rats could fit down drains. Dogs couldn't. Not proper dogs, like he was, anyway. Maybe little dogs. Lapdogs. Yappy things. If he was a little dog, he might still be able to catch him. Though Peter had always said a rat was a match for a little dog. Except he'd never had to prove it and-

What had he been thinking about again?

Oh. That was it.

A good joke.

He'd said it himself, too, once. Been on the right track; he'd almost had it, but he'd looked the wrong way.

The traitor is the last person we suspect.

"I know who the traitor is!" Sirius had been lying flat on the floor, but the epiphany caused him to sit bolt upright, hair sticking up as badly as James', though in his case it was more a matter of not having combed it since last week than natural untidiness, with one finger pointing at the ceiling.

"Really? Who?"

"It's the last person we suspect."

"Brilliant, Padfoot" Remus grumbled wryly, flapping one of the reports Dumbledore elicited from his operatives with the same degree of difficulty his professors had had in getting essays from them as students that he was sorting into alphabetical order because Sirius couldn't be bothered to at his friend. "You know, I think that's what they call an anticlimax."

"No- I mean, that's how we figure it out." Now he was on his feet, pacing in circles. "Whoever it is, it's someone we're telling everything. Not just Ministry business and political secrets. Little things. So they know how to get at us. Where we're going to be on a Friday afternoon after work. Look at Snape" he added darkly. "Dumbledore trusts him with everything."

"Yeah, and I tell Dumbledore where I'm taking Lily every evening so he can pass it on to dear old Severus in case he's lonely and wants to play third wheel. Give me a break. You suspect Snape first off. I suspect Snape. Moony? Wormtail? Do you suspect Snape?"

"Of course."

"He's a suspicious character."

"Right. See?" James nodded in triumph, squinting up at the dark shape stalking around the room. "So it's not Snape. Flaw in your logic. Sit down, will you? You're making my vision go all blurry."

"That's because you're not wearing your glasses."

"Oh. Point. Accacio" the spectacles in question zoomed down from the ceiling where they'd been hovering. How they'd got there in the first place it was safer not to enquire. "So if it's not Snape, by your theory, who is it?"

"No idea." Defeated, Sirius hit the floor again, a shaggy, boneless bundle of limbs. Sometimes the only way you could tell whether or not he had transformed into a dog was by being hit in the face with his tail. "Who's the last person you suspect?"

"You, Padfoot."

"...Right. Well, you're no help."

That had bothered him.

Of course Prongs suspected him least. He was his best friend. And until that moment, it had never entered his head that it might be James.

But that was how the logic went, wasn't it? Prongs knew everything. Knew things Sirius had forgotten, and vice versa. Handy trick, that. They'd always known where each other's homework was, even if they couldn't find their own. Besides, James was Who He Was. Every instinct, every brain cell, could find objections to the proposition that James was a spy.

So it could have been him. And God but that rankled. Gnawed at his guts like a termite on a chair someone had forgotten to put protective spells on. If he couldn't trust James, who could he trust? What was he fighting for if the life he was trying to preserve for himself was all a lie?

When word had leaked that Voldemort was hunting the Potters, it had almost been a relief; he felt guilty for that, to tell the truth.

Having your friend hunted by the Death Eaters wasn't anything out of the ordinary, though. Hundreds of people went through that, every day. Sometimes their friend even survived. There were places to go, precautions to take. Denounce James as a defector he couldn't. Protect him he could.

Except he couldn't, obviously.

Even though he'd spent hours planning it all out.

Never drop a plan that works, no matter how many times you've used it.

Wouldn't have been the first time he'd lied for James.

So what had possessed him?

Stupid, a thousand times over, but, in his defence, it had seemed like a good idea at the time. Nobody would suspect Peter. Come to that, nobody had, but not in the sense he'd meant.

Somehow, that didn't seem so funny as it had before.

Speaking of which, where was he now?

How long had it been?

The street, the people- or what was left of them- were gone. No light, no sound and he was sitting on something hard and damp, with more splinters than he thought were absolutely necessary.

Had he died, too?

No. Some Muggle play Lily had put away neatly on a high shelf, like something she didn't want touched, which was the surest way to make him take it down and read it, had suggested that death was a boat. No one'd ever said death was a cell, though. That was what he was in. One of the holding cells they put prisoners in before they were tried. He'd seen them before.

Never really analysed them, though. When he got out of here, he'd have to talk to Frank Longbottom about having some candles and better chairs installed in them.

Except he wouldn't, because some day the Death Eaters and Voldemort would sit in these cells. They deserved far worse than a bit of darkness and a few splinters for what they'd done, but those would do for a start.

A cell, then. That was all right. Or as close to all right as anything could possibly be, though he didn't recall how he'd got here. Hadn't Apparated. Maybe a portkey? Or someone had put him on a broomstick?

Soon he'd be taken before a court. Maybe get out on bail for a bit. He had money, they couldn't set it so high that he couldn't pay it, though he mightn't ever be able to afford to eat again.

Once he got out, he could see Dumbledore. Or Moony. Moony would believe him, once he heard the facts.

Probably wouldn't think it was funny- but neither did Sirius, now. In fact, he felt rather sick. Those people, all taken apart like a jigsaw puzzle, and James and Lily and- Harry. Somehow, he had to do something for Harry. Because he'd promised Prongs he'd look after him when he'd been named godfather, and he kept his promises, unless they were the sort you made to professors and employers and they didn't count.

All he had to do was tell Remus and he'd think of something. Always had been good in a crisis. Kept his head. Except on the full moon, which was when you were thankful that James usually kept his head, too.

Maybe he wouldn't listen, though.

They hadn't talked much since he'd decided the werewolf was the traitor. It was that logic again because, after James, who was the last person he could imagine playing double agent?

Remus Lupin. The obvious candidate. Clever, patient, almost fanatically loyal to Dumbledore out of gratitude, protective of everyone's rights so he could justify being so jealous of his own, such as they were. Couldn't be Remus. Ergo, it must be.

Wherever he was, all those sly, suspicious looks Sirius had shot him of late, all his growing reticence, his sudden bursts of hostility, would be slotting into place in Moony's mind. And he'd told him, told him in a deliberate attempt to feed misinformation to the enemy, that he was the Secret Keeper.

Enough to set him laughing again, almost.

Caught like a rat in a trap. But the rat had got away.

Dumbledore, then. To Dumbledore he would plead his case.

Remus' view of the world had always been a little skewed, anyway.

"You are, aren't you?"

"I am what?"

"Don't be dumb, Remus, you're a- werewolf."

Confronting him had been messier than they'd expected. They'd been so pleased with themselves when it had finally clicked, after half a year of seeing through his dissembling but not being able to make out what was on the other side, and elated when the notes in the textbook they'd huddled over together in the library while Remus had still been absent had all but confirmed their suspicions that they'd pounced on him when he returned, triumphantly waving their evidence under his nose and badgering him to verify their hypothesis once and for all.

Instead of answering, he had looked- angry, or disappointed, with him it was sometimes hard to tell- and fled the room as if they'd pelted him with silver.

"Give him space," James had said, and Peter had concurred, with remorse in their eyes. "We shouldn't have done that."

In all likelihood, they were right, but tact wasn't Sirius' strong point, so when he hunted down the boy- wolf- creature- whatever he was, and found him skulking in the Great Hall, staring at the false sky, he hadn't been able to help asking again. All he was after was an answer.

"You know everything. Why're you asking me?"

"'Cause. Are you?"

"Yes."

"Cool."

That had got his attention. Remus, still looking like death minus a coat of green fuzz from the recent full moon, had turned incredulous eyes on him. "Cool?"

"Yeah. Sounds like fun. I mean- once a month, you get to do whatever you want, and nobody'll dare stop you. If it was me, I'd eat Filch."

A bemused blink. "It's not quite like that, you know."

"Yeah it is." Now Sirius sounded envious, envisioning all the teachers and Slytherins he might make into meals if he turned into a ravenous carnivore. "You get the teeth for it, don't you?"

"Sirius, it hurts. You hate pain."

"I could take it, though."

"And you can't think straight. Maybe I'd eat you. Or you'd eat James. Can't tell people apart, or remember anything properly, afterwards."

"Oh. Well, you'll just have to find a cure."

"Don't you ever pay attention in Potions?" Coaxing Remus from furious down to exasperated was probably an improvement; Sirius wasn't quite sure. When he was mad, he went quiet. Now he might be in for a lecture. "There isn't one."

"Invent one. You'll be famous. Or James and I will. Peter can help stir it."

"You're insane, you know that?"

"Yep. And you know what else?"

"What?"

"I'm gonna come up with a way to eat Slytherins and remember it."

"I could always just bite you."

"That's not funny."

"You're a wimp at heart, Sirius Black."

"I'm not the one who's hiding in the hall, am I?"

"Yes, you are. You're here too. Remember?"

"Huh. Hadn't thought of that."

He had found a way, too, and there was no disputing it: being a ferocious carnivore was a lot of fun. Even if he'd never got around to eating any Slytherins.

More light, now.

And he was lucid. Really lucid, instead of in fits and starts. That was different. Not necessarily better, but different.

So were his surroundings. This was nowhere he'd ever seen before, except in books and photographs. A lumpy cot, a dirty floor, a barred door. Shapes in cloaks and cowls with breath like a hyperventilating athlete roaming the corridor outside.

Either he was in a Muggle monastery, or this was Azkaban.

Somehow, he didn't feel at all holy.

Had he been tried and convicted then?

His memory came up empty. Inconclusive. There were lots of things he didn't recall. But he thought he'd have come to for Dumbledore, if he'd spoken to him. Or even Crouch; his hectoring tone had a way of piercing everybody's comfortable insensibility.

No trial, then.

Maybe that was funny. Lots of things had seemed funny recently, he knew that.

No. On proper reflection, James and Lily and the Muggles being dead and Peter being a traitor hadn't been funny, and this wasn't, either.

'Funny' didn't belong in Azkaban. Better not to laugh. Laughter drew the Dementors, and they could drive you mad faster the more you resisted.

Think of something else.

That's what he'd been trying to do since this nightmare started. Might as well keep it up.

Hard to think of anything though.

Anything good.

Only- he was innocent.

That was something.

He was innocent.