firecracker ???

A few hours earlier, the door shut behind Lyra, leaving only the sound of her footsteps echoing down the corridor. Then even that faded.

Remus Lupin remained in the doorway, his figure tall and quiet. Regulus hadn't moved from where he stood—his face composed, unreadable. The silence that followed was taut, heavy with the sharp breath of just-missed disaster.

Harry's chest rose and fell.

They weren't done yet.

"Right," Sirius said after a moment, raking a hand through his hair, "so... how the hell did you know?"

Harry looked at him. "I heard you."

Sirius blinked. "You what?"

"A few weeks ago," Harry continued. "You and Regulus. You were in a classroom. I had the Invisibility Cloak. I overheard... all of it."

"All of it?" Regulus asked, voice low, eyes narrowing slightly.

Harry nodded. "That Sirius didn't betray my parents. That you're a double agent. That Peter Pettigrew is alive."

Sirius let out a low whistle. "Well. That would've saved a lot of shouting earlier."

Regulus muttered something under his breath that sounded suspiciously like, "Typical Gryffindor."

Ron, still cradling his leg awkwardly, stared between them in horror. "Wait—what?"

"Peter's alive," Harry said simply. "He's been alive this whole time."

"Scabbers?" Ron croaked.

"He's not a rat," Harry said. "He's an Animagus. He's the one who betrayed my parents. Not Sirius."

Ron looked from the shaking ball of fur in his lap to Harry, then back again.

"No," he said stubbornly. "No, he's not. He's my rat. He's always been my rat—"

"He's not," Sirius said. "And I can prove it."

He looked to Remus.

Lupin nodded, already raising his wand. His expression was distant, exhausted.

"Transform," Lupin said clearly.

The rat squeaked, tried to run—but it was surrounded. Lupin pulled out his wand.

"Transform now," he repeated, voice sharp.

There was a ripple, a shuddering, grotesque crack of magic.

Bones stretched. Skin shifted. Fur disappeared in a slick ripple.

Suddenly Peter Pettigrew sat trembling on the floor.

He was balding, hunched, smaller than Harry expected—and exactly as pathetic as he imagined. His watery eyes flitted about, landing briefly on Sirius, then Regulus, then Lupin. And finally—Harry.

"Harry," he whispered, scrambling to his knees. "Harry, please—please, listen—I never meant for it to happen like this—"

Harry's jaw clenched. He didn't answer.

Peter crawled forward slightly, eyes wide. "Your parents—they were my friends—I didn't know—he was so powerful—I didn't know what else to do—"

Sirius stepped forward, his wand twitching.

"You knew," he said, voice low and deadly. "You knew what you were doing."

Peter flinched. "Sirius—please—please, you know me—you knew me—we were friends—"

"You were James's friend," Sirius hissed. "You were Lily's friend. You were my friend. But you sold them to him. You let them die knowing you'd be rewarded. You let me rot in Azkaban for twelve years while you skulked in the shadows, sleeping in a warm bed while I lost everything."