Facts:
Veritaserum was a powerful truth serum. The potion effectively forced the drinker to answer any questions put to them truthfully, though there were certain methods of resistance. Use of this potion was strictly controlled by the British Ministry of Magic. (Source: Harry Potter Wiki)
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In the evening of the 2nd of September, Ed was in his dorm room, he was preparing to talk to Dumbledore. He closed Peter's cage with a cloth, and waited for Harry, who has also changing his clothes to a more casual one.
"Ready?" Ed asked to the green-eyed boy.
Harry nodded weakly as he fixed his collar, "Yeah."
"Right, step closer to me." Ed ordered, which Harry complied. He walked towards Ed, and before he even stop, he had already arrived at Dumbledore's office, there, he saw that Dumbledore was pacing around, wandering about something.
The old man then noticed the two arriving, "Ah, to what are you doing here Ed? Harry?"
"Business." Ed said, straight to the point, seemingly didn't want to talk to Dumbledore. Ed then walked to his desk and put the cage on top of it. "I need your help cleaning a mess that was made by the ministry and by your negligence, again…"
Dumbledore hummed, "What negligence are you talking about Ed?"
"Sirius Black of course." Ed said casually, earning the attention of Dumbledore, "He's innocent."
Dumbledore frowned when he heard the statement of the boy, "Do you have any evidence of this Ed?"
"Sirius didn't kill my father, Pettigrew did!" suddenly interrupted Harry.
"Peter Pettigrew is dead Harry… they found the-"
"Finger of him." Ed continued, placing his hand to the cage as it's shaking now, knowing that Pettigrew what was coming for him. "Yet didn't find a body… you see, this is your negligence on both of the ministry and you..." Ed said, "The ministry didn't investigate the actual murder, they threw Sirius into Azkaban without trial… as for you and your 'friends', you didn't investigate it as well, he was your ally, your friend, yet abandoned just like that." Ed snapped his finger, making the cloth disappear, revealing a frantic rat.
Dumbledore frowned even more at the statement, then he looked at the frantic rat, "And what is a rat doing here if I may ask?"
"You should know Dumbledore, you're their headmaster after all." Ed said as he open the cage and pulled the rat out of it. Then he threw the rat to the middle of the room and cast a Animagus cancellation spell when the rat was still on the air, making Pettigrew changed back to his normal form and slammed to the ground using it.
"May I present to you, the traitor." Ed announced, Pettigrew was shaking right now, there's no way he can run away from the greatest white wizard from all time. "D-D-Dumbledore…
Dumbledore walked to the small man and frowned, "Peter…"
"H-H-He's lying Dumbledore! It was Black who went to the dark lord! He tried to kill me remember?!"
"So, we've heard." Ed said sarcastically, stealing Remus's words. "Show us your left hand Wormtail if you want to prove your innocence."
Peter then paled at the mention and instantly cowered, Ed then walked to him in an attempt to reach his left arm, but he backed away, fearing the truth. Ed sighed tiredly as he saw what transpired, he open his palm and made Peter frozen, his body was surrounded by black and blue particles, scaring the coward.
"W-What is this!?" he shrieked, Ed just stood the in silence and swiped his hand, then Peter suddenly floated, his body is now making a cross, and he still can't move because of the spatial pressure.
Ed then looked at Harry, who was taken aback at the display of magic. "Harry, open his left wrist will you?"
Harry blankly nodded and quickly walked to Peter and opened his left wrist, revealing the dark mark.
"W-What's this?" Harry questioned, a bit afraid at the tattoo.
"The dark mark Harry." Dumbledore finally break his silence, "A symbol of Lord Voldemort's follower."
"Is this enough proof to you Dumbledore?" Ed sneered.
Dumbledore stared at the cowering Peter intently before saying, "Harry, can you call Professor Snape and Professor Lupin here? Quickly, please, and tell Professor Snape to bring Veritaserum."
Harry once again blankly complied and quickly exited the room, leaving the two alone. Ed then walked to Peter and casted a sleeping spell to temporarily knock him out, so he won't hear his weeping and moaning.
The room then went silent, the atmosphere was tense, not to mention Ed knows that Dumbledore could've prevented the death of Arisanna.
"So…" Ed broke the silence, "The name 'Oath-breaker' ringing any bell?" Ed asked sarcastically.
Dumbledore basically tensed a bit as he remembered that name, "Yes…" he said weakly, "A nickname to me given by your guardian owl… for me to always remember my failure."
"So not only you killed your own sister, but you indirectly caused the death of another man's sister… not a really good track record is it?" Ed sneered at Dumbledore, making the old man sighed.
"I intent to fix my mistakes by protecting you Ed…"
"Well, if you want to fix you mistakes then revive my aunt." Ed said decisively.
Dumbledore then went quiet after that, waiting for the rest to arrive, then a couple of minutes later, Snape, Lupin, and Harry hurriedly entered the headmaster's office, confused at what made the headmaster abruptly called them.
"Is there anything wrong Dumbled-" Snape was about to ask, but when he saw a knocked-out Pettigrew floating in the middle of the room, he stopped. "Is that… Peter Pettigrew?"
"Alive and well Severus." Dumbledore said, "And it seemed that the ministry caught the wrong traitor that night… Peter cut his own finger, turned into a rat and ran away, hiding in the form for almost 12 years."
"You mean…" Lupin said weakly.
"Sirius Black is innocent." Dumbledore nodded.
"So, he's the traitor?" Snape asked the obvious with cold fury in his eyes.
"Obviously." Ed rolled his eyes.
Snape glared at Ed for a second, then walked closer, "I'm assuming the Veritaserum is for confirming it?"
Dumbledore nodded, "Ed, wake him up."
Ed snapped his finger, making Wormtail woke up, once he wakes up, he saw his old friends in front of him.
"S-Severus… R-Remus… My old f-friends…"
"So, it's you who betrayed us Peter…" Lupin said in cold fury.
"I'm innocent Remus! It really is Black! He's got dark powers given by the dark lord himself!"
"I must admit, Peter, I have difficulty in understanding why an innocent man would want to spend twelve years as a rat," said Lupin calmly.
"Innocent, but scared!" he refuted.
"Give him the serum Severus." Dumbledore said calmly. Snape nodded and forcefully made Peter drank the Veritaserum, making his face looked blank.
"Are you the secret-keeper of the Potters Peter?" Dumbledore asked.
"Yes… Sirius and I switched at the last moment, making me the secret keeper…"
"Of course…" Lupin murmured, "Who would believe the coward Pettigrew be the secret-keepers of the Potters…"
"Did you tell Voldemort their location Peter?" Dumbledore asked again.
"Yes, it was me or them…" Peter said again blankly, "And I choose me."
Ed saw that Snape grabbed his robe hard, Ed can tell that he's holding his fury. After that, Dumbledore asked a couple more questions to Peter, which Ed didn't listen, instead he was looking out the window, it was raining outside, a couple of thunders can also be heard.
'Can we get this over with already…' Ed thought in his mind, 'it's quite tiring.'
Ed then heard some bickering from his back, but he ignored it, instead he just continued to listen the rain sounds, calming himself down, but then Dumbledore interrupted him with a question.
"What do you think Ed?"
Ed turned around, "Hm?"
"How do you think we should deal with this and proved that Sirius Black is innocent?"
Ed hummed, "Surprise the Minister and the Wizengamot." Ed said, "Don't tell this to anyone yet, well, maybe tell some trustworthy people. We can't tell Fudge about this, he would instantly dementor's kiss Peter to hide the scandal, so maybe contact Amelia Bones to set up the trial abruptly, avoiding any interference."
Dumbledore nodded, "Any other objections?" he asked to the other two adults, but the two rather agreed with the plan.
"Then don't contact Amelia Bones through official means." Ed said, "Convinced her by talking to Sirius and showing her Peter."
"Amelia is Sirius's old love as well." Remus added, surprising everyone, "So it should be quite easy to convinced her."
"I didn't know that." Ed murmured, "Anyway, maybe ask her niece to call her here, I hear she's quite protective of her. Oh, bring my aunt as well, Aunt Narcissa."
Dumbledore narrowed his eyes, "Are you sure that's a great idea Ed? it would be disastrous if she knows."
"Oh, she already knows." Ed said, "She's hiding Sirius at the moment." Ed announced, surprising everyone at the room.
"What? Malfoy's mother hiding Sirius?" Harry, who had been quiet all this time suddenly spoke up.
"She is Harry, she wants to revive the Black family, he is the last Black after all…" Ed said. "Don't protest Harry, Sirius is your godfather, you don't want to miss your chance to meet your only family now do you?"
Harry was hesitant, but ultimately nodded.
"Right then." Dumbledore cut of their conversation. "Severus, please call Pomona and Minerva here. Remus, can you guard Peter?"
Severus nodded and exited the room, while Lupin also nodded, he casts an Animagus spell to Peter, he was about to take the rat but it wouldn't budge from the particles.
"Oh, sorry." Ed undid the spatial pressure of the rat and pointed at the cage, "That's an unbreakable cage, use that if you want."
Lupin muttered a thank you and put Peter in the cage rather roughly, locking him up.
A couple of minutes later, Professor Sprout and Professor McGonagall suddenly entered the room, Dumbledore then explained the situation to them, surprising them, they couldn't believe that Sirius Black is actually innocent, and instead, it's Peter Pettigrew who's the traitor.
"Pomona, can you call Ms. Bones here? Minerva, would you please guide young Harry here to his dorm room, and after that, can you bring Mr. Ronald Weasley here? We wanted him for questioning."
Both of them nodded and rushed outside, Ed once again waited in the room, looking outside the window, admiring the rain. As minutes gone by Ron and Susan Bones appeared in the room, Dumbledore talked to them, Ed didn't really hear anything, instead, he was playing with his wand, fidgeting it with his finger like a drumstick, and not a couple minutes later, Dumbledore suddenly looked at Ed and called him.
"Ed, come here." He spoke.
Ed stared at the old man and walked up to him, "Something wrong?"
"Just setting up a schedule, when can you bring them here?" Dumbledore asked softly.
"I can bring them at 9th, Auntie has some investigation she needs to do on her own first…"
Dumbledore nodded, "Okay, can you owl your aunt to the school Ms. Bones?"
"I don't understand Professor… why my aunt? Why not my father or mother?" she asked in confusion.
Dumbledore just smiled, "It's rather complicated Ms. Bones, I'd rather tell your aunt in person…"
The girl sighed as she nodded reluctantly, "Very well Professor, I'll owl my aunt to come to the school on the 9th."
Dumbledore patted the girl's shoulder and said, "Much appreciated, now, I believe you deserve a rest, you can go back now Ms. Bones."
The girl nodded and walked outside, heading to her own dorm room, then Ed proceed to go back to where he stood, beside the window. Ed saw that Dumbledore was questioning Ron about the rat, but he didn't really listened, he just watched the clouded skies, trying to find some peace in his heart.