Disclaimer: Not my characaters, as I'm not JKR. I'm not making any money from this, either.

A/N: This story assumes the existence of a romantic relationship between Remus Lupin and Sirius Black. There will be, in subsequent chapters, mild to moderate "slash" content. This chapter is rated PG-13 for an unpleasant transformation sequence.

Leading the Pack

"I sometimes felt guilty about betraying Dumbledore's trust… he never knew I had led three fellow students into becoming Animagi illegally…" – Remus Lupin, in Prisoner of Azkaban

Prologue

"I just wish there was some way we could make you better."

"There isn't, Sirius. Not really. There's only –"

"What?"

"It's dangerous."

"Tell me anyway."

"No. Not yet."

Later:

"Oi, Lupin! What's that book you've got there?"

"Never you mind, James Potter."

"Peter said you checked it out from the Restricted section. How'd you manage that?"

"Never you mind about that either."

Part One: The Least Haunted House in Britain

Three twelve-year-old boys were huddled in an unlit hallway, in front of a battered wooden door. The door looked as though it could be blown over by a light sneeze, but it was held in place by the strongest charms, spells, and incantations that Albus Dumbledore could muster.

Something Dumbledore had left off, however – deliberately – was a silencing spell. The noise from within the room was perfectly audible, not only to the three boys outside it but also to the residents of the nearby village, Hogsmeade.

Finally, one of the boys – blond, plump, and smaller than the other two – spoke. "I hear the villagers think this place is haunted."When neither of the other boys replied, he went on, "In a way, they're right."

When this didn't solicit an answer, he continued: "They call it the Shrieking Shack."

Peter Pettigrew had known the other boys for just over a year, but he still hadn't figured out that when they ignored him, he should just keep quiet.

"They say –"

"Shut up, Peter."

Peter fell into an unhappy silence. The other two boys seemed lost in the hideous sounds emanating from the room beyond. The house was without light, and the other boys had not lighted their wands and forbidden Peter to use his. All Peter could see of his companions came from the reflected moonlight of a nearby window: both were tall for their age, lean, and dark-haired, and although they hadn't noticed it they were sitting in precisely the same pose. In fact, if not for the reflection off James Potter's glasses, Peter wouldn't have been able to distinguish him at all from Sirius Black.

There was a tremendous thud against the door, and it seemed as though the whole house shuddered. There was a scrabble of nails – not quite yet talons – on the other side. And screaming.

Begging.

"Please! Please! Please! Help me! I know you're there – help me – let me out – I need you – please don't leave me in here – please!"

A sob escaped from Sirius Black's mouth, and he jerked convulsively.

James Potter grabbed his friend by the arms, pushing him down, half afraid – more than half – that Sirius would acquiesce to the frantic pleas.

The voice on the other side of the door lowered in pitch but not in volume. Sometimes, past the midpoint of the transformation from boy to wolf, Remus Lupin was still capable of bursts of speech. As a body slammed against the door – and none of the boys wanted to think what that body looked like right now – a horrible, half-animal voice screamed at them.

"Hunt!"

After that, human vocal cords completely gone, the wolf that had been Remus Lupin merely shrieked and howled in inarticulate rage. Sometimes, the cries would suddenly muffle. Peter was secretly thankful for those moments when the cries lessened, though he knew he shouldn't be: it meant that the wolf was probably ripping itself to shreds. Werewolves hunted only humans, but the wolf didn't understand that it was also partly human. It could smell the humanity on its own limbs, and attacked itself.

There was another horrifying thump against the door, and Peter fancied he could hear wood splintering.

"What if the spells don't hold? What if he breaks through the door?"

"Don't worry, Peter, you'll live," said Sirius Black, but he didn't sound at all comforting when he said it.

"Do you think so?"

"Of course. I'm closest to the door: he'll come for me first. Then, when he's done savaging my ruined corpse, he'll turn on James, because James will be trying to get him off me. You should have plenty of time to escape."

Peter let out a sob, and James said, "Siri, don't be cruel to him. He's afraid."

"Then why is he here?"

"Because he's Remus' friend," said James gently. "That's why we're all here." He turned to Peter. "We're all afraid," he said with kindness. "It'll help if you remember what a powerful wizard Dumbledore is. We're perfectly safe where we are."

The screams and howls escalated, but all three boys knew they hadn't yet reached their peak.

Sirius Black placed his hand against the door, and rested his cheek just above it, his eyes closed. "It's Remus who's in the real danger," he said softly. His voice dropped to a whisper. "We're here, Remus," he said. "Your friends are here."

He nearly said, "We love you," but he didn't; he stopped himself. Sirius felt a comforting hand stroking his back; then James nudged him down from against the door.

"I want to show you something."

James Potter grabbed his schoolbag, and pulled out a book.

"So help me, Potter, if you're going to do homework, I'll –"

"Hush," said James, and Sirius fell silent at once. Against the backdrops of tortured howls, James brought out his wand, and said "Lumos." Light shone from the end of the wand, and Peter scooted toward it. He was in awe – not just of the light, but by the easy way that James had commanded it. He was still working on that charm – he could get the light to stay for a flicker or two, but no longer. The light emanating from James' wand was strong, steady.

"I thought we agreed no lights?" asked Sirius, but it was curiosity and not anger that filled his voice.

"This time, we have something worth seeing," said James. "You know that book that Lupin's been hoarding? The one he makes a show of reading, then won't let us see? I nicked it from under his mattress." He raised the light over the title of the book: Animagus Transfigurations.

"What's an – Ani – Anima –" started Peter.

"Animagus," said Sirius in a thick voice. "It's a wizard who can turn himself into an animal at will. You know, like McGonagall. It's very advanced magic. They don't even teach it until after you graduate, and even then you have to pass special tests just to prove you have the aptitude. And you have to be registered. Otherwise it's totally illegal. Unregistered Animagi – at least, those who survive – can be sent to Azkaban." But nonetheless he ran his hand over the gold lettering on the cover.

"I think we could do it," said James.

"It takes years of work."

"We have years. Five and a half years, in fact. Depending how good we get, we could do it well before we graduate."

Sirius was still stroking the book cover, as though it were a long-lost pet.

"Um, why – why do we want to be – Animagmusses?" asked Peter.

Neither of the other boys bothered to correct his pronunciation, but James said, "We could stay on the other side of the door with him. We could keep him company. We could keep him from hurting himself."

"What? Are you mad?"

There was another terrific thump against the door, and the cries became even louder.

"Werewolves only attack humans," said James patiently.

"We're humans."

"But werewolves don't know the difference between animals and Animagi," said Sirius. "The wolf would just see other animals. It wouldn't be compelled to kill or bite them."

"Are you sure?"

"Positive," said Sirius Black. "I read all those books on werewolves, remember?"

"And they talked about Ani – Ani –"

"An-ih-MAY-guy," said Sirius slowly. "No, they didn't. But only because no one's tried it before."

"So we'll be the first," said James.

"Agreed."

Both boys looked at Peter, who blinked at them, then nodded, more because he was afraid of being left out than anything else.

Sirius smiled at him, one of the rare times that he seemed pleased with Peter. "You can be a little dormouse, Petey. That way, if we're wrong, he probably won't even notice you."

"Be nice to him, Siri."

"I am!"

There was a moment of quiet, of calm, and the boys realized that the howls from inside the room had stopped.

"No way it's dawn," whispered Peter.

"Dawn's hours away," replied Sirius in hushed tones. Dimly, they became aware of a snuffling sound on the other side of the door. The wolf had caught their scents. It wanted them.

Hunt.

The growling began, low and deep and throaty, and sent corkscrew shivers down each boy's back. Then there was a barking, almost doglike. If you tried, really tried – and Peter was really trying – you could pretend that it was just a big barking dog, not a bloodthirsty predator.

Sirius, against all logic, stroked the door affectionately. He spoke to the wolf on the other side. "Soon," he promised. "We'll be in there with you soon."