"Wait, Dursley, hold on! There's got to be some kind of misunderstanding here," Lupin said quickly.
He'd acted on instinct just moments ago, but deep down, he trusted Sirius completely. Lupin had always found the events of years past suspicious. Sirius's betrayal seemed too far-fetched, too sudden. After all the time they'd spent together, Lupin couldn't believe his best friend would turn on James, let alone sell him out to Voldemort.
But his doubts had never mattered.
He was a werewolf, shunned by the wizarding world. The Ministry wouldn't listen to a word he said. If he dared defend Sirius, they'd likely brand him an accomplice and toss him into Azkaban alongside him. After all, Voldemort did have a squad of werewolves under his command.
"Sirius, explain yourself, now!" Lupin urged.
Sirius, however, didn't seem in a rush. He looked at Harry for a long moment before saying, "You look so much like your father, James."
"So you killed him," Harry replied, his tone calmer than expected.
Sirius gave a bitter smile and shook his head. "I won't deny it. I did play a part in James's death. It was because of me."
"But if you knew the whole story—"
Sirius still wasn't getting to the point.
"The truth is you killed him, and now you're here to kill me," Harry cut in, his voice growing colder.
Lupin's face practically turned green listening to their exchange. What is this guy doing?
Why couldn't Sirius just spit it out instead of playing riddle-master? Couldn't he at least say, "I didn't kill your parents"?
Did he think he had this in the bag or something? Arrogant, reckless, and prideful—years in Azkaban hadn't changed him one bit.
"Professor Lupin, are you sure you want to side with this fugitive?" Dudley asked, his expression calm but piercing.
His words caught Sirius's attention, and it dawned on him. "Dursley? Wait, I remember now. You're Lily's sister's kid—the one who married that fat Muggle? So, you're a wizard now. What house? Hufflepuff?"
"I'm in Slytherin," Dudley replied coolly. "And you're exactly as my mother described—crude, rude, and utterly classless."
Lily had introduced Petunia, Vernon, James, and Sirius after graduation, but it was far from a pleasant meeting. It ended in a bitter fallout, with Lily and Petunia cutting ties for good. Young James and Sirius were, well, unique—rebellious in a way that, to the Dursleys, screamed delinquent troublemakers and aimless street punks. Naturally, Petunia, as the older sister, worried, and Vernon, as her husband, felt he had to do something about it.
Predictably, the two wizards put them in their place. If Snape couldn't escape their torment at school, a Muggle like Vernon didn't stand a chance.
"Oh, Slytherin," Sirius sneered, his disdain skyrocketing. "The den of criminals. You're just as repulsive as that pig of a father of yours."
Lupin knew it was over the second those words left Sirius's mouth.
Sure enough, a spell shot out, blasting Sirius across the room. His body slammed into the wall with a thud.
"Don't you dare insult my uncle, you filthy criminal," Harry said, his face dark and his tone ice-cold.
"Expelliarmus!" x2
Hermione and Lupin cast simultaneously, their spells canceling each other out.
"Please, wait! Sirius didn't mean it!" Lupin shouted, desperate to de-escalate.
"Didn't mean it? So it's fine to insult someone's parents just because you 'didn't mean it'?" Dudley snapped. "And Slytherin's a den of criminals? You might not know this, but the first recorded dark wizard in Hogwarts history came from Gryffindor."
"Put away your arrogance, Azkaban's prisoner," Dudley said, rising from his seat. His towering frame, rippling with muscle like a small mountain, radiated an intimidating presence that hit both Lupin and Sirius hard.
Sirius had to admit, the moment his eyes met Dudley's, he felt a twinge of fear.
"I was going to let you explain yourself, but your stupidity is beyond disappointing."
You had your chance, and you blew it.
Dudley's gaze swept over Sirius, his voice slow and deliberate. "You don't deserve to be my brother's godfather."
"You know?" Sirius froze, stunned.
Dudley ignored him, turning to Harry. "Harry, this idiot didn't betray Aunt Lily. Someone else did. But make no mistake—Lily's death is because of this fool."
"When Voldemort was hell-bent on killing Aunt Lily and your parents, the Fidelius Charm kept them safe. As long as the Secret-Keeper stayed silent, Voldemort would never find the Potter house. And the original Secret-Keeper? That was this prisoner right here."
"Things could've stayed fine if they'd just kept it that way."
"But this genius," Dudley sneered, "decided to get clever. He thought switching Secret-Keepers would outsmart Voldemort. Brilliant plan, right? Even if Voldemort and his cronies caught him, they'd never find Lily and your parents. Truly a stroke of genius from a brain barely bigger than an amoeba's."
Dudley's cold laugh cut through the room as he stared at Sirius.
"And, surprise, it went exactly as you'd expect. The new Secret-Keeper ratted them out to Voldemort."
"Prisoner, calling you the reason Aunt Lily and Harry's parents died isn't an exaggeration."
Sirius's arrogance had cost him his best friend and left Harry an orphan. He wasn't the direct killer, but he was the catalyst—the one who set it all in motion.
Overwhelmed with guilt, Sirius sank to his knees. "Yes, it's all my fault. I got James and Lily killed."
"But how do you know all this?" he asked, his voice trembling. Dudley's account was so vivid, it was as if he'd seen it all himself—but that was impossible.
"Because I caught the one who betrayed them," Dudley said.
Sirius's eyes widened, a manic glint of joy flashing across his face as he lunged toward Dudley. "Give him to me! Give him to me!"
"Sirius, no!" Lupin tried to stop him, but it was too late.
Before Sirius could even touch Dudley, a massive wooden hand pinned him to the ground.
"Maybe this will teach you to behave, Azkaban's prisoner," Dudley said, barely sparing him a glance.
This man—failure as a friend, godfather, and person—wasn't worth his time.
"Harry," Dudley said, shaking his sleeve. A tightly bound rat fell out—Ron's pet, Scabbers. With a flick of his wand, Dudley cast a spell. The rat rapidly grew, transforming into an ugly man, still bound tightly, the vines expanding with him.
"His name is Peter Pettigrew," Dudley said, kicking the man. The pain jolted Peter awake from his unconscious state. "He's the one who betrayed Aunt Lily and your parents."
"Now, you can do whatever you want with him."