Severus Snape was watchful. He had learned early on that it was the only way to be if you wanted to survive. He knew the dark passages of Hogwarts like he knew his own crooked nose in the mirror, or all the instructions for brewing in his potions textbook. He knew which members of his own house would not hesitate to hurt him and which would ignore him or, at worst, spit out an unimaginative invective before strolling away laughing. He knew too which students from other houses would persecute him.
He could not decide who was worst of all; Lucius Malfoy and his cronies, a year older, or James Potter and Sirius Black from Gryffindor.
Sometimes he was certain it was Malfoy. He would be sitting reading in some nook away from the common room in the dungeons, a window sill perhaps or a chair in the corner of a disused classroom, and Malfoy would find him with his enormous doltish sidekicks and they would take his wand and taunt him and hit him or practise their curses and hexes on him and laugh as he screamed or writhed on the floor or bit his lip until it bled.
Usually, though, he thought it was the Gryffindors. They didn't usually hurt him, not physically, but in some ways the particular brand of public humiliation they specialised in was worse. He was a proud young man, only seventeen but with an adult and arrogant way of carrying himself that acted like a sort of signal to Black and Potter that here was someone whose life they could more or less ruin whilst avoiding punishment.
And of course, the worst of it all was that their friend was usually with them when they did it, and yes he pretended not to watch but no doubt he had seen sides to Snape - parts of Snape - that it made him blush angrily just to imagine.
Severus wished that he didn't, but he knew exactly why he didn't like their friend seeing his ongoing torment. It wasn't particularly that he felt guilty or weird or wrong for it, simply that he had learned whilst at Hogwarts that knowledge made you vulnerable. If you had something to hide, you were weak. He'd practised his occlumency for hundreds of hours but he still could not shake the feeling that some day this emotion would get him into trouble somehow, that he could be forced to do something against his will only to keep that knowledge a secret or to protect it.
The trouble was that he fancied Lupin.
He had tried without success to argue himself out it. It wasn't that he was a boy, or even a Gryffindor, but… Lupin was painfully thin, scruffy, always looked so knackered, had terrible taste in friends, couldn't brew a potion to save his life. Severus had always imagined that he'd only fall for tall handsome men with quicksilver brains and sure sensitive hands who could make potions blindfolded until one day he'd had to sit next to Lupin in a lesson - Charms - and Lupin had given him a Chocolate Frog and smiled at him and whispered an answer to a question that Severus hadn't heard because he'd been lost in reverie. He couldn't help himself.
He thought Lupin probably liked him, or at least tolerated him. He knew about the skinny Gryffindor's love of chocolate - had learned after that day, his skill at covert watching coming into its own. Why would he have shared with him unless he liked him? And smiled at him too… though no doubt Lupin had no idea just how fascinating his smile was. He certainly didn't seem to.
And so he'd taken to following Lupin around from time to time. Nothing obvious, naturally, just enough to be able to bump into him sometimes and say hello - usually in the corridors but every now and then, when he was feeling bold, in the Astronomy tower (Lupin stargazing) or a quiet corner of the library (Lupin reading) or even in the Prefects' bathroom (Lupin flushed, wet haired, white towel wrapped round his waist, rippling scar on his left shoulder).
Severus wasn't particularly experienced in the ways of boys but he thought that Lupin always looked quite pleased to see him, the pleasure tinged with embarrassment and - perhaps - excitement.
And so, he started to talk to him.
He only did it when nobody else was around, as much for Lupin's protection as his own, but when he had tracked the boy for a while and had assured himself they were alone, he would engineer meetings and then maybe drop his schoolbag or rush round a corner into the unsuspecting Lupin, giving himself the chance to apologize and then strike up a conversation.
Lupin seemed quite eager to respond and so they would stroll together and Severus would tell him about the worst of the Slytherins; Lucius and Bellatrix Black who was quite quite mad, and her sister Narcissa who looked down on everyone in the school and Macnair who liked killing things and Rodolphus Lestrange who was so stupid he could barely walk and talk simultaneously. He didn't talk about how much he hated Black and Potter of course. He knew that wouldn't get him anywhere.
Sometimes he would turn the conversation towards schoolwork. He would pay Lupin minor compliments, tell him that his skills in Transfiguration or Defence were really very impressive and Lupin would blush fetchingly and respond that Severus was the best potions student in the school (which he already knew). He had found out in his observation of Lupin that he liked muggle books and he would talk to him about the classics and about words. He told him the words he especially disliked (flobberworm, quiddich, oleaginous, pureblood). He talked about the songs on wizarding radio that were always playing in the Slytherin common room and how irritating and banal they were. Lupin, who was muggle-born, had lent him some records and told him the spell to make them play, and Severus seized that opportunity to tell him how similar was their taste in music. In short, Severus charmed Lupin.
Sometimes he forgot himself though, and he would talk about his own future and his miserable past. He explained how he never wanted to grow up like his father whom he hated with a passion that, he noticed, unnerved Lupin slightly until he told him just what Tobias Snape was like. Lupin's eyes went big and sad and Severus felt lust burn in his chest. Lupin had asked instead what would he like to become, and Severus didn't have an answer. He only knew what he wouldn't like to become, he said, and Lupin had smiled gently and nodded and agreed.
In turn, Lupin confided in Severus. He told him what it was like to be on the inside with Black and Potter and the pathetic Pettigrew, and he told him how he did like school, at least he tolerated it, but he couldn't wait to be an independent adult. He said he thought his life would be happy when he was training to be a Healer (because that was what he was planning), living free, maybe with one of his friends, and going to the pub with colleagues and the cinema and even the theatre sometimes. In short he wanted to be able to do the things he liked and make his own decisions.
Severus had thought that he didn't look particularly happy when he said all these things, though he ought to have been beaming. He asked him why not, and Lupin said that he couldn't believe that all of that would actually be his. He said surely something would go wrong before that could happen.
When they were having that particular discussion they were in one of the gloomy twilit study alcoves in the library; one of the History of Magic ones because no one ever ventured there. They were standing side by side, leaning against bookshelves stuffed with dusty old books that hadn't been opened for a hundred years, and Lupin was staring at his shoes, one lace untied, scuffed and badly in need of polishing. He made what was clearly a big effort and lifted his gaze ahead, then turned and faced Severus.
That was all Severus needed. The proximity and the scent of Lupin was just too much for him to bear, and he slid a white finger under the top button of Lupin's robes, loosened his tie, leaned in and kissed him with a ferocity that momentarily surprised them both until Lupin responded and there was no room for surprise or doubts or anything except kissing and sliding hands under layers of school uniform and grinding against each other, gasps and pants of pleasure, gentle and not-so-gentle bites on necks and ears and lips.
Severus was dazedly gratified to notice that Lupin had moved so he was pressing up against him, shoving him into the books so that clouds of dust billowed around them as he took control of the kissing, firm hands taking hold of Severus's wrists and anchoring them by his head so that Severus was - unexpectedly, delightedly - dominated by the strange skinny Gryffindor who was so much stronger than he looked.
The kiss could potentially have gone on and on, and much more could have happened, but Madam Pince happened upon them and giving them both a tongue-lashing ('Honestly, I'm surprised at you two - such depraved behaviour in the presence of The Books! How could you, you nasty little boys!') sent them packing.
Lupin had whispered in Severus's ear that they should meet that night in the prefects' bathroom and given him one final kiss that made Severus's knees feel like they may give way, before he had left with a backward glance full of mischief and longing. Severus stared after him and wondered what sort of genie he had unleashed from its bottle, for a few moments with trepidation which gave way almost immediately to the sweetest kind of anticipation.