"But...he's Wormtail." It was all that James could think to say, standing here in front of a Padfoot who was too old, too scarred, too thin. As it all sank in, he started to see the cracks that had been there. But where he'd suspected Remus--oh what a bloody fool he'd been--it had been Peter. And James had given him the power to destroy their lives. "One of them...he's a Death Eater? Where is he? I'll kill him."
He focused on that thought, let the rage overtake the guilt and despair that threatened. Rage, he could deal with. He could do something with rage, and right now he wanted to tear that little rat limb from limb with his bare hands. As terrible as the rage was, he thought he'd be very successful.
Then the rest of Padfoot's words sank in. No way back. Nothing to go back to. "They're dead, aren't they? Lily. Harry. He killed them." He didn't need Sirius to spell it out. "Where are we? How did I get here? How'd you get here?" He had so many questions but asked them mostly out of habit. He didn't really care about the answers right now. Not when his wife and child were dead, and there was no going back.