Sirius is twenty-one years old. He shares a shabby, one bedroom flat in Muggle London with Remus. It is small, but reasonably clean, because Remus cares about that sort of thing, and because Remus feels he must do something with his time between his infrequent jobs and helping with the Order. He spends a lot of time roaming around the flat.

Sirius has a job with the Ministry. He is training to be an Auror, following James down that career path once he realised that he was not going to see a knut from his parents, and he was going to have to do something with his life. Being an Auror is exciting, and working for the Order is doubly so, but the excitement is overshadowed by the oppressive sense of doom which permeates the Wizarding world.

Voldemort and his Death Eaters are taking over, slowly but surely. They are not the majority by any stretch, but there are enough of them, and there seems to be no way to halt their rise without stooping to their methods. What wizard of conscience could bring himself to resort to an Unforgivable Curse? Good, brave, heroic witches and wizards are found dead in their homes. Sometimes, entire families simply disappear. The Death Eaters are systematically wiping out any members of the Wizarding community who oppose their pure-blood ideals.

But almost worse than this overt terror is the fact that few of those who work for Voldemort do so openly. Most keep their identities hidden, and no individual ever claims responsibility for their crimes. They leave only their Dark Mark - the ghostly green skull and snake - drifting over the carnage they leave in their path.

No one knows whom they can trust. Even witches and wizards who do not espouse Voldemort's pure-blood philosophy might be frightened or coerced into serving him with threats against their persons, friends, or families. Of those willing to risk such threats, some might yet fall victim to the Imperius Curse, and be forced to comply against their will.

Everyone is frightened. The Wizarding world appears to be heading down a dark path, from which no return seems possible.

James Potter still faces the world with his usual confident smile. In a world where reluctance to make plans for a future which may never come is common, he marries Lily Evans, and they have a child together. But Sirius can sense the uneasiness in James as well.

With growing alarm, Sirius watches the progression of events. Late into her pregnancy, Lily and James are cornered by Death Eaters. They make a narrow escape. At first, it seems to be a random attack on a wizard couple who are clearly on good terms with Dumbledore, but as the Potters are targeted a second and third time after the birth of their son, it becomes clear that they are being hunted.

Sirius is terrified for his friends and tiny godson, but is powerless to do anything to prevent the attacks. Voldemort and his followers always seem to know where the Potters are and when they will be alone.

Dumbledore tells James - and James eventually confides to Sirius - that he knows why Voldemort has taken a special interest in the Potter family. James will tell him no more than that, saying only that too much knowledge could be dangerous. Dumbledore has also gently suggests that someone among the Potters' close circle of friends and family, willing or not, may be passing information to Voldemort.

Sirius is stricken by this idea. He knows it's not himself, obviously. He cannot imagine that it is Peter, with his timid nature and hero-worship of James. Besides, Peter has been increasingly absent from their little get-togethers of late. James's father, an Auror like his son, had been killed in the line of duty the previous year, and his mother had been found dead in their home beneath the Dark Mark on the same day. Lily has barely spoken to her Muggle sister since their parents were killed in an automobile accident during their last year at Hogwarts.

That only leaves Remus. Remus, who is a quick liar, and a natural keeper of secrets. His lycanthropy. His relationship with Sirius. These things are known only to their closest friends, and only because he wishes them to know. Sirius has seen him turn his easy, sincere smile on others - watched the suspicion fade from their eyes.

But it can't be Remus, can it?

Sirius is sure he knows him as well as one person can know another, and if there were a treacherous bone in Remus's body, he would surely know about it. However, Sirius cannot deny that, as the situation has worsened in the Wizarding world, Remus has slowly but surely been withdrawing into himself.

He barely speaks to anyone, even to Sirius, and has become edgy and nervous. Every now and then, Sirius catches Remus giving him long, appraising looks, quickly shifted once he realises Sirius has observed him doing so. He is increasingly absent. Sometimes he mumbles excuses to Sirius about his missions for Dumbledore and the Order, but more often than not, he goes without a word, and returns days or even weeks later, with no explanation.

Sirius is busy, too, of course, but the Ministry and the Order together make less use of him than the Order alone seems to make of Remus. He cannot bear to think, though, that Remus might be the traitor. It is too painful. He considers the possibility instead that Remus is seeing someone else, but that is little better. Surely Sirius would be able to smell that sort of infidelity on him in his canine form. Better not to think about it at all.

And then in October, James comes to him with an idea straight from Dumbledore which should, in theory, keep Lily, Harry, and himself safe. Only James, with his wicked sense of humour, cannot resist adding his own twist to the idea. They need a friend to perform the Fidelius Charm, and keep the secret of their location. Everyone knows how close James and Sirius are; they will assume he is the natural choice. But it will be Peter. The perfect bluff.

Sirius catches James's excitement while his friend is there, but once James leaves, the implication of the plan hits him full force. If James is confiding his plan to Sirius, then he does not suspect him. And if he is using Peter to implement it, then he cannot suspect Peter. That has to mean that James thinks Remus is the guilty party, and James would never think such a thing without good reason, even though he has told Sirius not to worry. Perhaps Dumbledore has confided something to him.

By the time Remus returns that evening, Sirius has managed to convince himself that he must be the traitor. He does not ask where Remus has been, and Remus does not volunteer the information. He has only been gone for the afternoon this time and has returned bearing food. Perhaps he has only been to the shops. Or maybe shopping is simply a convenient excuse to get out of the house and secretly pass on information about the Potters.

Sirius wonders what the Death Eaters have offered Remus. Maybe they have some Dark spell which can cure or control Lycanthropy. Sirius does not know if there is any such thing. His own research never turned anything up. But then, he never delved very deeply into the Dark Arts.

As the evening draws on and the silence stretches between them, Sirius begins to formulate subtly pointed questions that he could ask to draw Remus out. But when he tries to implement them, they fall short.

"Where have you been?"

"Out."

"What were you doing?"

"Had to get some stuff."

The conversation goes no further.

As the sun sets, they go about making a silent supper, not touching one another. After the meal, Sirius goes to do the washing up, but Remus stops him with a hand on his arm which he pulls back a bit too quickly.

"I - I'll do that," he says. "You can go and -" He turns toward the sink, not bothering to finish the thought.

Unexpectedly, anger flares in Sirius, and he storms off to the bedroom, slamming the door behind him. He picks up an empty mug from the bedside table and hurls it against the door, where it smashes noisily.

That was a mistake, he thinks. Now Remus will come.

He does not want to deal with Remus just now. Maybe he should have gone out instead of hiding in the bedroom.

Too late now.

Only Remus does not come. Sirius listens for him at first, but there is no sign that Remus is coming to investigate the noise.

Maybe he's gone out again.

No, Sirius can still hear the water running in the kitchen. He flops onto the bed and glares angrily at the ceiling.

Well, fuck him! He's a stupid bastard anyway. And maybe he is the one selling out James and Lily. James thinks so. It must be him. Fucking traitor. He deserves - something. Something rotten. One day I'll think of something bad enough, and he'll deserve it. Maybe I should just leave.

But he knows he can't. Sirius has only known two ways of living: life with his family, and life with Remus. In wartime, when so much is uncertain, people have a strong desire to cling to the familiar. He does not want to be without Remus, whatever Remus may be.

Besides, he rationalises, someone needs to be here to keep an eye on him. I have to protect James and Lily and Harry. It's up to me.

When Remus comes to bed an hour later, Sirius is still angry, still staring at the ceiling, determined to find a way to punish him for what he must be doing.

Remus steps over the broken pieces of ceramic scattered across the floor, undresses, gets into bed, and shuts off the light, turning away from Sirius. The full moon was less than a week ago, and it has taken him an unusually long time to recover this month. He has been tired and listless for days. He does not say anything to Sirius as they lie in the darkness.

After a while, Sirius gets up and undresses as well. He lies in bed staring at Remus's back in the dim light of the Muggle street lamps that filters through their thin curtains. He can tell from the set of Remus's shoulders and from his breathing that he is not asleep.

Sirius has a sudden, overwhelming urge to make Remus feel something - say something. Their life has become gray with silence and suspicion. He longs to just come out and say, "Dammit, Remus, what the hell is going on?" But he cannot make his mouth form the words.

Instead, he says it with his body. He presses against Remus's back, hot and angry and insistent, accusing and demanding at once.

Prove your innocence, his body almost shouts. Prove you're still Remus, and that this hasn't all been just a lie to go along with all your other lies - a way to hide and protect yourself.

Remus does not resist - hardly moves at all - as Sirius uses him hard for long minutes. Neither of them makes a sound, apart from Sirius's harsh breathing and his brief, choked sob of release. Afterward, he turns away without a word, and tries to make himself fall asleep quickly.

The sounds of a boy werewolf crying quietly so as not to wake his roommates haunts his dreams.

Sirius shivered in his cell in Azkaban, lost to memories which the Dementors artfully manipulated to elicit the most delicious emotional responses from their victim. Despair, helplessness, and especially heartbreak were their favourite meal. Sirius did not even see them anymore. As soon as they approached, he entered a dreamlike state, peopled with a terrible mixture of his own memories and finely-crafted nightmares.