Snape and Lily's daughter

Traitor

"And why did he fake his death?" Harry said furiously. "Because he knew you were about to kill him like you killed my parents!"

"No," Lupin said. "Harry—"

"And now you've come to finish him off!"

"Yes, I have," Black said.

"Then I should've let Snape take you!" Harry said.

"Harry," Grace spoke. "don't you see? All this time we've thought Sirius betrayed our mother and your father, and Peter tracked him down — but it was the other way around, don't you see? Peter betrayed our mother and your father — Sirius tracked Peter down —" Grace was still crying.

"THAT'S NOT TRUE!" Harry yelled. "HE WAS THEIR SECRET-KEEPER! HE SAID SO BEFORE YOU TURNED UP. HE SAID HE KILLED THEM!"

"Harry... I as good as killed them," Sirius croaked. "I persuaded Lily and James to change to Peter at the last moment, persuaded them to use him as Secret-Keeper instead of me... I'm to blame, I know it... The night they died, I'd arranged to check on Peter, make sure he was still safe, but when I arrived at his hiding place, he'd gone. Yet there was no sign of a struggle. It didn't feel right. I was scared. I set out for your parents' house straight away. And when I saw their house, destroyed, and their bodies... I realized what Peter must've done... what I'd done..."

"Enough of this," Lupin said. "There's one certain way to prove what really happened. Ron, give me that rat."

"What are you going to do with him if I give him to you?" Ron asked Lupin.

"Force him to show himself," he said. "If he really is a rat, it won't hurt him."

Ron hesitated, but then handed Scabbers to Lupin.

"Ready, Sirius?" Lupin asked.

Black had already retrieved Snape's wand from the bed.

"Together?" Black said quietly.

"I think so" Lupin said, holding Scabbers. "On the count of three. One — two — THREE!"

The rat fell on the floor and started becoming a human. Grace joined Harry, Ron, and Hermione on the corner of the room.

"Well, hello, Peter," Lupin said pleasantly. "Long time, no see."

"S—Sirius... R—Remus..." Pettigrew's voice was squeaky. "My friends... my old friends..."

"We've been having a little chat, Peter, about what happened the night Lily and James died. You might have missed the finer points while you were squeaking around down there on the bed —" Lupin said.

"Remus," Pettigrew gasped. "you don't believe him, do you...? He tried to kill me, Remus..."

"So we've heard," Lupin said coldly. "I'd like to clear up one or two little matters with you, Peter, if you'll be so-"

"He's come to try and kill me again!" Pettigrew squeaked suddenly. "He killed Lily and James and now he's going to kill me too... You've got to help me, Remus..."

"No one's going to try and kill you until we've sorted a few things out," Lupin said.

"Sorted things out?" Peter squealed. "I knew he'd come after me! I knew he'd be back for me! I've been waiting for this for twelve years!"

"You knew Sirius was going to break out of Azkaban?" Lupin asked. "When nobody has ever done it before?"

"He's got dark powers the rest of us can only dream of!" Peter shouted. "How else did he get out of there? I suppose He-Who-Must-Not-Be-Named taught him a few tricks!"