Disclaimer: None of the characters and most of the plot isn't mine.

Summary: What if Severus Snape and Remus Lupin were not enemies? What would have happened when Remus came back to teach in Hogwarts during Harry's third year? Follows the events of 'Prisoner of Azkaban' with a few liberties I allowed myself. A Snupin story.

I saw somewhere someone calling Snape-Lupin Snupin and it was so cute and I bet that if Snape ever hears of it he'll explode with rage but I just had to use it.

Prologue

25.05.1978

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"Severus… Oh gods, babe yes, right there…" Eighteen years old Remus Lupin's head was tilted back to give his lover better access to his neck. He was currently leaning against the wall of the Astronomy tower, while his boyfriends' lips and fingers were working their magic on different parts of his body,

"Will you be quiet, Lupin?" Severus hissed, detaching his mouth from the pale flesh that was rapidly reddening under his ministrations, "You're making such a racket, the entire school can hear you!" Before he could resume his previous activity Severus found himself being pushed backwards by a glassy eyed Remus,

"So what if they do?" He asked, his voice still slightly shaking by his heightened emotions, but his face was clouding fast, "I already told you I don't really care if people know about us. I love you, Severus." Severus shook his head and turned away from the other teen to face the night sky. He wrapped his arms closely around his body his shoulders hunched.

Remus racked his hands in his hair, already regretting bringing up the subject. He knew what Severus was going to say, he's heard the dark haired teen's arguments countless times before and frankly- he didn't agree with any of them. So what if they were from different houses or that their friends hated each other or any of Severus' other objections. Remus didn't care; he stopped caring a long time ago. At first it was exciting, having a clandestine affair in a castle full of horny teenagers, passing encrypted notes to each other telling where and when they should meet, having to stay quiet during their time together. But now, after nearly six months Remus wanted more. He wanted time; he wanted to be able to work his way slowly over Severus' body, mapping every part that would make the other boy moan. He wanted a bed, no more hasty and hurried shags against the nearest available wall, he wanted to be able to watch Severus coming down from the height of sex all relaxed and sated. So basically he was prepared for everything Severus might say,

"I'm going to take the Mark." Everything, except that. Remus stared in shock at the back of his boyfriend's head, hoping beyond hope that he heard wrong or that Severus was bluffing. The Slytherin turned, his expression sad to look at Remus, "I'm sorry."

"How can you do that? How can you follow that madman?" Remus demanded angrily, this was absurd! He knew that Severus had found a sense of belonging and acceptance in the Slytherin house with those who believed in the Dark Lord's way. After the way his own father treated him, Remus could understand why Severus felt that Muggles were in the wrong but he still couldn't believe that Severus will go as far as dedicating himself to that cause. "When did you decide that? Why didn't you console me?"

"Because this isn't your decision or your care." Severus answered with a shrug, "I'm the one who made it and I'm the one who will own up to it." Remus rubbed his eyes, feeling lost. Severus was always the secretive type, who wouldn't say anymore than he absolutely had to and didn't show emotions often. At that moment the realization dropped on Remus like a ton of bricks- he'd been fooling himself all along, Severus never really loved him the way he did Severus. For Remus their relationship meant graduating and trying to make it in the outside world together. He couldn't wait to get their first flat together, not having to hide anymore. But apparently Severus had already decided where he was going and what he was going to do and Remus had no room in his future plans. Being from different houses was one thing; having a boyfriend in the grasp of an evil cult- as Remus saw the whole ordeal was something altogether different and Remus knew he couldn't carry on diluting himself.

"So that's it? I don't have a say here?" He tried one last argument, but the look in Severus' eyes told him that he had lost.

"I'm sorry Remus." Remus shook his head, a lump forming rapidly in his throat. He bit his lip, trying to hold himself together. He would not give Severus the satisfaction of seeing him breaking down. Severus made a feeble attempt at reaching towards the other teen but Remus waved his hand away,

"Just go. I need to be alone." Severus closed his eyes briefly, before nodding once and leaving the room. As soon as the door closed behind Severus' back Remus sank to the floor, trying to breath through his nose to hold the tears back. What a fool he had been- Severus Snape, the school potions star and most enigmatic teenager he's ever known, had played him like a damn violin and for what? Sex.

While Remus' romantic heart was all but ready to drop to his knees and declare his love in front of the whole school Severus was just interested in sex it seemed, and was willing to toss Remus aside as soon as his true passion stood in their way. It hurt. It hurt so badly and Remus gave up on the fight with himself and let the tears fall. It was over, and he lost.

A/N: It's a bit on the short side- I know. It's just to sort of give you a clue to what's going on. So, Severus and Remus were lovers when they were in school and broke up. Now, what will happen when they meet again, 15 years later?