"James wake up!" Sirius shook his friend violently until he opened one eye a tiny crack.

"Whassa matter?" James murmured and pulled the quilt over his head.

"James this is important. Wake up. It's Remus."

Five minutes later the two boys had disappeared underneath James's invisibility cloak. They crept downstairs and made their way to the Whomping Willow.

"How are we supposed to get passed the branches?" James hissed. Sirius pulled the cloak off and pointed. The tree was still.

"Dumbledore did something and it just froze," Sirius explained as he picked his way around the branches. He found the gap he had watched three people climb into earlier. "Come on!" he pulled James into the hole and they found themselves in a large passageway. They walked for a while until James stopped suddenly in his tracks.

"Sirius, wait!" he whispered and put his finger to his lips. "Listen." Sirius listened and heard a distance noise. Growls and barks and bangs and screams.

"We've got to help him!" Sirius started running forwards but James pulled him back.

"We've got to get out of here!" There was panic in James's voice and eyes that told Sirius not to argue. The pair ran as fast as they could towards the end of the passageway. James hoisted Sirius out of the hole and they pulled the cloak back on. Only when they were back in the common room did Sirius ask James what was going on.

"I just worked it out," James sounded slightly out of breath as he collapsed into a chair.

"Worked what out?"

"Think about it," James held up one finger. "Remus is always ill at a certain time every month- the time of the full moon." He put up another finger. "He gets led to an abandoned secret tunnel where nobody can see him." Sirius still looked blank so James sarcastically put up another finger. "And he got full marks on that Defence against the Dark Arts essay about werewolves."

It was as if a light had clicked on in Sirius's head. He stared at James, open mouthed. One of his best friends was a werewolf? It couldn't be...it just couldn't...

"Hi guys!" Remus said brightly as he joined them at breakfast the next day. Only Peter answered. "What's up?" he asked as Sirius and James shot nervous glances at each other.

"We know, Remus." Sirius whispered.

"Eh? Know what?"

"We followed you last night."

"What's going on?" Peter demanded.

"You followed me?" Remus whispered.

"What's going on?"

"So you know everything?"

"What's going on?"

"I'm a bloody werewolf!" Remus hissed at Peter who squeaked and slid away from Remus on the bench. "It's ok. I guess I should have known you'd figure it out." He smiled weakly at Sirius and James who smiled nervously back.

"It's ok if you don't want to be my friend anymore. I'd understand. But there's nothing I can do about it." Remus stood up and left the hall. James turned to Sirius and Peter who both nodded.

"Remus! Wait up!" the boys ran after their friend. They grabbed him by the shoulder and swung him round.

"You idiot of course we still want to be your mate!" Sirius patted him clumsily on the back.

"Yeah we don't care if you turn into a monster once a month!" James grinned. "In fact it's kinda cool!"

"Oh my god!" Sirius put a hand to his head dramatically. "I have had the best idea!"

That night the four boys crept to the library under the invisibility cloak. The proceeded directly to the restricted section. They silently searched for the book they needed.

"Got it!" Peter squeaked and ran excitedly to Sirius. Sirius opened the heavy book and they all gathered round. They looked at pictures of people changing into animals. There was a witch who kept transforming into a sheep and back again, and a wizard who kept shrinking into a bee.

"Are you sure you want to do this?" whispered Remus. "It looks hard."

"Dead sure!" Sirius stuck out his fist. James placed his on top, as did Remus and Peter. "The Marauders of Hogwarts stick together! Forever!" he said.

"Forever!" the other three repeated before pulling the cloak over themselves and the book and going back to bed.