She's got a point. He hates to admit it but she does have a point. And she's facing him so she doesn't see but Remus sees the guilt return full force to Black's face; as though staying here doing nothing is not what he should have been doing, as though Harry really is in danger.

"I'm going to tie you up." Remus says in warning, and casts the spell, despite Tonks' irritated growl.

"Will you let me explain?"

Bloody hell. He's going to go to hell for this. He nods.

Sirius relaxes, as much as the ropes will allow, and looks terribly grateful; it's almost painful to see.

"Thank you. Thank you Remus. I – shit I don't know where to start."

"You said Harry's in danger." Charlie Weasley says, startling Remus, who had forgotten he was there. "What's he in danger from?"

Sirius shifts slightly and it takes Remus a moment to realise that he's bracing himself for something. "Peter. Peter Pettigrew."

Remus snarls and drops his wand in favour of throwing himself at the traitor. How dare he!

Remus barely has time to make contact with Black before Tonks and Weasley are pulling him away.

"Hold him back Charlie." Tonks says. "I won't let Sirius escape."

Remus struggles against Weasley's hold but can't escape; and quite foolishly his wand is now on the floor. He feels something sticky on his hand, and looks down to discover blood. He looks back at Black, sure he hadn't had enough time to cause any sort of wound. Black looks shaken by his attack.

"Can you –" He shudders. "Can you show Remus the photo again please?"

Charlie releases one arm around Remus to pull the photo out of his pocket but tightens the other one in warning.

"What are we looking at?" He says, "What does my family have to do with any of this?"

Black disregards the question, instead speaking directly to Remus. "The youngest boy, Remus, he has a pet rat on his shoulder."

Remus squints at the photo, barely able to comprehend what Black is suggesting, but there is a rat on Ron's shoulder.

A very familiar rat.

There's no way...it's completely insane.

"How..?" Remus croaks.

"We switched." Black sobs. "It was all my idea, all my fault. I persuaded them to switch secret keepers. I was just too obvious, Moony, Peter would have been the perfect decoy."

Too obvious, Remus thinks sadly, not to mention too suicidal. He remembers clearly thinking during the war that Sirius was putting himself in far too many fights with people only too willing to kill him, he remembers thinking that it was a miracle he kept surviving.

"Keep going." For the first time he meets Sirius' eyes and almost has to look away at how much he still looks like his old friend.

"I persuaded them to swap. Everyone would know it was me and Peter would go into hiding. The plan lasted less than a week. It was only luck that I checked on Peter that night, and found the safe house empty, with no sign of a fight. I panicked and flew of to Godric's Hollow at once. But I was too late."

Everything he says comes out at a rush, as though he's been waiting twelve years to tell someone.

"What happened next?"

"Hagrid took Harry away on my bike and I went to find Peter."

"And you blew up a street to catch him." Charlie says flatly.

"NO!" Sirius shouts – well tries to, his voice still hoarse, it sounds more like a cackle. "No, I wouldn't put people in danger like that. Peter's the one who blew up the street. He cut off his finger at the same time to make sure they'd find remains and then he ran away. There was so much blood."

Remus completely collapses, only Charlie's arm keeping him upright. He believes him. God help him, he believes him.

"If one of you goes to the castle and fetches Peter then I'll go quietly to the ministry. Or anywhere else."

Does he think they're going to send him back to Azkaban? Does he think Remus is willing to lose him again?"

"I'll go." Remus says, standing up straight, and finally pushing Charlie's arm off of him. "Tonks can you contact Alastor Moody? He always liked Sirius, he might listen."

Tonks lights up. "He's my boss!"

He's...what? "You're an auror!?"

"Yeah, they're probably going to lose their job over this." Charlie mutters lowly. "Even if he's telling the truth this is a much worse breach of protocol than a little illegal dragon smuggling."

What?