“Albus! Albus! Have you heard! Merlin – it can’t be true! And Harry – where is Harry? No one seems to know anything!” Sirius caught himself on the edge of Albus’ desk, breathless and frantic.

Before he could say anything else, Minerva hit him from behind with a Petrificus Totalis. Just as she fired the spell at Sirius, she heard another voice – raw with pain and hatred – scream out, “Avada k—“

Minerva spun with a gasp, knowing she was already too late, but Albus was already incanting “Expelliarmus!” Snape’s wand flew out of his hand – a testament to Albus’ power – and the gathering Unforgiveable dissipated.

“Petrificus!” Minerva snapped, as furious with herself as with Severus. How could she have overlooked such an obvious threat? Severus had already vowed to kill Sirius for betryaying Lily – did she really imagine a former Death Eater would be satisfied with a nice, tidy trial?

She and Albus looked at each other, the two young men frozen into rigidity at either end of the office. Albus sighed heavily. “I will call the Aurors and inform them we have Sirius –“

“Albus!” McGonagall was again infuriated with the old man’s foolishness. “Don’t be ridiculous. We do not yet have the slightest idea what happened.”

“Minerva,” the Headmaster said patiently. “He was their Secret Keeper. His betrayal was the only thing that could have led to their deaths. Of course we know what happened. I know this must be hard for you as his former head of House, but Sirius Black will go to Azkaban.”

“Albus, what is wrong with you tonight? Have the events of the evening addled your wits? We have Sirius and Veritaserum. I will know exactly what happened and why before a single Auror will be called.” At his frown, Minerva glared at him. “So far this evening, the only Unforgiveable has been uttered by Severus Snape. Do you really wish to call the Aurors now? I certainly don’t!”

Albus grumbled but acquiesced.

Within a few short minutes, both men had been spelled into chairs and securely bound there. Albus handed the Veritaserum over to McGonagall with a “this was your idea, get on with it” wave of his hand, and slumped into his own chair.

Tonight had been almost more than he could bear. Every stress in his extraordinarily long life seemed to have revisited him tonight with a vengeance. He was utterly, utterly exhausted. For too long he had been the only thing holding back the Dark. Now he could, at long last, release the burden that was the entire Wizarding world. All he wanted was for this night to be over, as quickly as possible. He had lived long enough to see and defeat two Dark Lords; he was ready to rest, if only Minerva would stop interfering! Once he had realized the Potters were dead and Voldemort vanquished, he had rapidly worked out what still remained to be done . Sirius, the obvious traitor, banished to Azkaban. Orphaned Harry safely ensconsed with Lily's sister. With all those loose ends tied up, he could finally - with a clear conscience - collapse.

But he had reckoned without the iron will of a single Scottish witch.

Minerva first went over to Severus. His glare was strong enough to incinerate stone, but she was unmoved. “Albus has your wand. If you want to see it again, I strongly suggest you agree to sit quietly in that chair. If you agree, I will release the spell.” She thought she saw a flicker of grudging agreement, and cautiously un-Petrified the man.

She cast a silent sticking hex at the same time. The hex wouldn’t hold a grown wizard for more than a few seconds, but that would be long enough for Albus to re-immobilize him if necessary.

Once the spell was gone, Snape rolled his shoulders and hissed angrily under his breath, but he didn’t try to move from his chair. Minerva gave him a grim nod. “We may need your help to interrogate him, but if I think I can’t trust you…” She trailed off meaningfully.

Visibly gaining control of himself, Snape gave an abrupt nod, then turned a look of loathing onto Black.

McGonagall took a deep breath and un-Petrified Sirius. Unlike Severus, he was bound by strong ropes to his chair. “Professor!” Sirius yelped. “What’s happening? Why did you attack me? And why are you letting that greasy Death Eater loose? Didn’t you see him try to kill me? He attacks an Auror with an Unforgiveable, and you’re keeping me tied up?”

“I know you are an Auror, Mr Black,” Minerva said tightly. “But I’m more interested in your other role just now. That of Secret Keeper. How did the Dark Lord know where James and Lily were, Sirius?”

Sirius slumped in despair – at least as much as the ropes would allow him to move. “It was all my fault,” he whispered brokenly.

“Bastard!” Snape suddenly spat. “Murdering swine!”

Sirius’ head jerked up. “What! How dare you call me names, Snivellus! You’re a bloody Death Eater!”

“I may have joined the Dark Lord, Black,” Snape snarled back, “but at least I didn’t lead the Dark Lord to my best friend.”

“No,” Sirius yelled, “you just made her His target!”

Severus reeled back as if struck, and Minerva hit both men with a silencing spell. “Enough!” she cried. “I will have order!” She glared at both, as if she were back in her Transfigurations classroom.

It was only after both men had stopped mouthing obscenities at each other and were once again sitting quietly that she released the spell. “Sirius – how could you have joined Voldemort?” Minerva asked, her voice breaking. “After everything you and James had meant to each other…”

“What?” Sirius stared at her. “Minerva, what are you talking about?”

“You admitted you betrayed Lily and James. I don’t understand what made you take the Dark Mark. What did He promise you? Riches? Power? Was it your family's influence?”

“Minerva, I would never join that maniac! You know me better than that,” Sirius looked hurt.

“But you said –“

“I said it was all my fault, and it was. I was the one who convinced James and Lily to switch Secret Keepers.”

The response was electrifying. “YOU WHAT?” burst from three throats simultaneously.

Sirius slumped and shook his head. “I told them to switch Secret Keepers after I was nearly captured in a Death Eater ambush a few weeks ago. I was worried that if the next one was successful, I might be tortured into revealing the Secret. I told James and Lily that they should pick someone else, but not tell anyone. That way, I’d still be the target, but if I were to be taken, they’d be safe.”

“But – but – why didn’t you tell us this immediately?” Minerva gasped. “Who is the new Secret Keeper? That must be the traitor!”

Sirius shook his head. “Impossible. Don’t you understand? The new Secret Keeper was Peter.” Minerva looked at him in surprise.

“Pettigrew? I would have thought Remus…”

Sirius looked grim. “Voldemort has been attracting too much support among the werewolves. We couldn’t be sure if Remus’ loyalties might not be compromised in the future. You know what pack structure is like – Remus fights it better than most, but James wouldn’t take the chance. That left Peter.” Sirius gave a sort of half-smile. “He didn’t want to do it. He was so frightened. But he agreed in the end. That Gryffindor courage came through. I promised him that no one would ever know, so he’d never be a target. He’s a true friend.”

“You moronic imbecile. You idiotic prick. You arrogant ignoramus.” Snape’s low monotonous voice was brimming with bitterness.

Sirius glared at him, stung. “What’s your problem, Snivellus? Just because you don’t have any friends –“

“You fool! How can you be so blind? Pettigrew must have betrayed you!”

“Never!” Sirius shouted back.

“Who else? How else? Open your eyes, you stupid prat!”

“Enough!” Minerva shouted again. “Severus – did you ever see Peter with the Dark Lord?”

Snape shook his head. “But the same argument I made about Black would hold for Pettigrew. The Dark Lord would have taken pains to keep me ignorant.”

Ignoring Sirius’ mutter of “That wouldn’t be hard!”, Minerva thought for a moment. “Were there any new Death Eaters in the last few months? Anyone you don’t know?”

“It’s not as if the meetings are tea parties where one goes around introducing oneself,” Severus said cuttingly. “Most of the time we are hooded and masked. The costume was specifically designed to prevent easy identification, Minerva. The whole ‘illegally torturing people to death’ thing, you know – it tends to make people camera shy.” He ignored McGonagall’s ferocious scowl. “Besides, if You Know Who didn’t want me to see Pettigrew, he had only to avoid Summoning us together.” Then he paused, a thought striking him. “There was one though…" He frowned in thought. “I had just arrived after being Summoned and saw someone slipping away. At the time I thought it was odd – that someone was leaving just as the meeting was beginning.”

“Could it have been Pettigrew?” Minerva asked, ignoring Sirius’ adamant head shaking.

“It could have been Pettigrew,” Snape retorted. “Or Black. Or you, for that matter! Get it through your head, you daft witch. With Death Eater regalia in place, you can’t recognize your own mother.” Snape paused as a thought visibly struck him. “Although now that you mention it –“ he broke off, shaking his head. “No, it couldn’t have been Pettigrew.” Minerva’s shoulders slumped, while Sirius grinned in triumph.

“Why not?” she asked, defeated. “Because I just recalled – You Know Who called to me and I turned away, but not before I saw the person change.”

“Change?” Minerva echoed.

Behind her, Sirius suddenly stiffened. “It was an animagus – the person became a rat.”

A piercing howl of rage and grief ripped from the bound man behind Minerva, spinning her around.

“Noooooooo! Peter, you bastard! How could you? We trusted you!” Sirius screamed, writhing in his bonds.

“Mr Black! Sirius!” Minerva flew to him, but it was several minutes before he was coherent.

“That traitor,” he finally panted, tears running down his face. “Pettigrew is a rat animagus. We all became animagi to be safe around Remus. James was a stag; I’m a dog. Peter a rat. We didn’t tell anyone, ever. Only Lily knew. It was the Marauders’ biggest secret.” Sirius gasped in anguish. “Oh, Peter – how could you betray us all like that?”

Snape’s own face was working. “You left Lily’s safety in the hands of that idiot?” he demanded. “You stupid, careless –“

“I’ve got to go,” Sirius’ head snapped up, grim purpose in his eyes. “I’ve got to get that bastard.”

“Not if I get him first!” Severus made to rise, was caught by the hex, and before he could cancel it, Minerva hit him with a binding spell.

“No one is going anywhere until I verify all of this!” she said, turning a gimlet eye on the silent Headmaster. He looked exhausted – every one of his many years – but he nodded weary approval.