Too bad I don't own Harry Potter or anyting related to it (or Remus... Yummy...). A certain Ms. Rowling does, because the got the idea faster than me.
1. Beginnings
11-year-old James Potter stood happily on platform 9 ¾ and watched as everyone scurried from place to place, loading their bags and chatting with friends. He didn't have a whole bunch of wizard friends, because his family lived in a pretty secluded part of England, but he was excited to make some. He looked eagerly around for other kids his age and immediately spotted a tall, chiseled boy with gray eyes and black hair that fell elegantly around his eyes. His robes were perfectly fitted and clasped at the neck with a large silver brooch. He looked politely bored. James hadn't known this was possible. His mother and father were both tall, black haired, and beautiful. They were richly dressed and had a younger child in tow who was swaddled in silk and satin. James ran over and stopped short in front of the new boy, ignoring his mother's shouts for him to come back.
"Hi! Are you a first year, too?" he said, practically dancing with excitement. The boy looked at him for a moment, almost confused at his display of excitement, but he apparently decided that he didn't mind because he smiled broadly.
"Yeah. I'm Sirius Black."
"James Potter! Pleased to meet you." He had to push his overlarge spectacles pack up his sweating nose. Sirius extended his hand, and James shook it. They grinned again. Then James' mother walked over.
"I'm sorry about my son," she said, smiling fondly down at him. "Sometimes he buts right into places he doesn't belong."
"That's quite all right," said Sirius' mother regally. "Sirius is quite the little handful himself." Her hand tightened on her son's shoulder. "I expect, however, that I won't be hearing anything from the school about your behavior, correct, Sirius?" Sirius nodded glumly. The mothers made polite conversation for a few more moments, but Mrs. Potter pulled James away as soon as she could.
Once James had gotten onto the train and it had pulled away from the station, he romped up and down the aisles until they found a nearly empty compartment. The only person inside was a pale and sandy-haired boy. He was sleeping, and had dark circles under his eyes. There was a livid looking set of scratches on his cheek. He was already in his school robes, though their sleeves were much more close-fitting than James'. James plopped himself down. The boy he'd met on the platform walked into the compartment, dragging his large trunk behind him.
"May I join you?"
"Sure."
James helped him heave the trunk the last foot into the compartment and closed the door. Sirius sank down on the crimson seat and immediately pulled off the brooch, which James saw had intricate snakes winding all over it.
"I hate this stupid thing," he muttered, stuffing the brooch into his pocket and loosening the neck of his robes. James looked at himself. He wasn't even wearing robes, just some muggle pants and a button up shirt.
"Oh well. No one's telling us what to do now... hey! Let's have some fun...." He pulled out his wand. "I'm so happy I can finally have one of my own!" he said, still bursting with excitement.
"I know... Just think of all the pranks I can cause now I can use magic," Sirius said, an expression of rapture crossing his face.
"You like pranks?"
"Love 'em. My mum is really uptight, and it's so fun to leave spiders in her shoes or turn her hair green!"
"You're brave... My mum would flay me alive if I tried that," James said, awe in his voice. They were silent for a moment, and James' eyes fell of the boy sleeping in the corner.
"What do you think is wrong with him?" James asked quietly.
"I dunno. Maybe he just got over scrofungulus or something. I had a real bad case of it last year and I looked almost as bad."
"But what about the cuts?"
"A cat?"
"I guess." James held up his wand again and thought for a moment. "Do you wanna wake him up?"
"Okay." Sirius looked excited.
"No need, I am awake."
"Huh?" Sirius asked, startled.
"No problem... I woke up when you came in. But thanks. I didn't want to sleep anyway. My name's Remus Lupin, by the way," he said. His voice was hoarse and it caught in his throat, like he'd been yelling a lot recently.
"James Potter."
"Sirius Black."
"Hi."
"So you heard us..."
"Yeah, but it's okay. I bet I look really bad."
"So what happened to your face?" asked Sirius bluntly.
"Would you believe me if I told you I just got over a bad case of scrofungulus and my cat scratched me?" he replied.
"No," laughed James.
"Then I'm gonna tell you that anyway, because I like that explanation better than the real one." The boys chuckled. Sirius even went so far as to say,
"Remus, I like your style." They sat in silence for a little while, awkwardly trying to think up new topics for discussion. James took another valiant stab at conversation.
"So what house do you fancy?" James asked. "I really like the sound of Griffyndor, and my dad was in there."
"I don't care as long as it isn't Slytherin," Sirius said. "Most of my family is from there and I don't want to be in the same house as Bella and Narcissa. They're my cousins," he added after seeing the confusion on their faces. "They're really mean."
"Yeah, Slytherin's creepy... But I'm afraid I might be in there anyway..." Remus said, suddenly looking broody.
"Why?"
"I dunno. It's just a feeling. But I think I'd like Ravenclaw... or Gryffindor."
"It would be cool if we were in the same house," James said.
"Yeah. I'd love Gryffindor," Sirius said. They fell silent again, but this time it was companionable, not awkward.
"Hey guys?" James asked.
"Yeah?"
"Let's be best friends."
"Why?" Sirius asked, put out. "We don't even know each other."
"I know, but it would be cool to have best friends and I don't." he said.
"Me neither..." said Remus.
"Hah! I barely even know any wizards my age, and I don't really have any friends..." Sirius said.
"Then it's perfect. Friends?" he asked. They looked at him, Sirius with mild trepidation and Remus with buried anxiety, but then they smiled, almost at the same time.
"Friends," they replied.