I've pretty much finished writing this, it will be seven chapters (and, I am intending, an extra chap of -unfriendly smut which will get posted on my LJ, I'll link to it on my profile page when it's there - please be forgiving as I've never written proper PWP filth before!) and I'll be posting as and when. No doubt some reviews will speed me up... It's to a small extent an AU as it's set in an unspecified and Harry Potterless time frame, in a Hogwarts in which both Snape and Lupin teach, and in which there is not currently a war.

Letters are in italics.

Knowing you as I do, in some ways very well and in others not at all, I can only make an educated guess as to what you will do with this letter.

My prediction is that you'll incinerate it with an exasperated flick of your wand. Perhaps you'll regret it a little, you might think later that you would like to reread it. Most likely you won't. Most likely you'll dismiss it as the fevered ramblings of an unbalanced mind. I can assure you that my mind is not unbalanced, though. It's probably working better than it has for quite some years.

I can imagine your face as you're reading this, thinking what is the point? Very well, I will stop prevaricating before you feel compelled to give up reading.

I'm writing because I'm too much of a coward to tell you to your face that I love you.

Professor Snape sat up at this. He turned the parchment over but that was all. The anonymous writer had had his or her say, and had neglected to sign off. He considered acting upon the suggestion that the writer had made, that he would burn the letter, but agreed that it was possible he would regret such hastiness.

So, what to make of it? A prank? Very well, but it did not read entirely like a prank. If it was a practical joke, the joker had hit a subtle and rather credible note. Unlikely as that seemed, knowing the calibre of the minds that he taught and who were the most likely authors, it was surely more believable than that someone had been watching him and loving him and biting their tongue.

Still, the thought of someone coming before him, trembling and tongue-tied, to tell him that they loved him made him laugh out loud. A letter would be much the most sensible course if one wished to escape hex-free.

He did not feel confident of any chance of success in discovering the author's identity from the letter; it was surely carefully concealed. A prankster would not wish to be discovered, nor would a lover - not immediately, at any rate. That would surely destroy the whole point of an initial secret advance.

He dropped the letter on his desk and sat back in his chair, legs and arms crossed. Would he even attempt to uncover the author's name? That would likely be playing into their hands.

He shook his head, swept the letter under a pile of other paperwork and returned to marking the fifth-years' pathetic attempts at essay-writing.

Snape had, if not forgotten exactly, then mentally filed as a low priority, the letter he had received. Life proceeded much as usual, inching along in slow hours punctuated by painful stints at the staff table for meals. He prided himself on the fact that his behaviour and demeanour were entirely unchanged by the mysterious epistle, and fleetingly thought that its author must be at least a little disappointed.

After one particularly excruciating dinner, at which some of the teachers had a sprightly conversation about their love lives, he escaped and swept down to his rooms in the dungeons. The thunderous look he wore slid off his face when he let himself into his study and he noticed the brown owl standing on his desk and drinking wine from a half-finished goblet.

'What are you doing here?' he asked the owl, then mentally told himself off for talking to a bird.

He stroked its feathery head as he unfastened the letter - same paper as the previous one - from its leg. It hooted a couple of times in a happy sort of way before taking off.

He unfolded the letter and sat himself down.

I of all people should know how difficult it can be to trust. You gave no indication whatsoever of having received a rather extraordinary letter - congratulations. I suppose you put it down to a practical joke. A reasonable thought, though I can assure you that it was entirely heartfelt.

I have written again - not because I want to irritate you, or want anything from you that you would not freely give - because I want to convince you that I meant every word I wrote before, and I mean every word this time.

Honestly, I know I would be an awful lot happier if I could satisfy myself with some other person. At least, it would be easier. Still, you cannot choose, can you, Severus? I would not have chosen you, knowing my pitiful chances of you returning my feelings, but there you have it.

I can't stop myself loving you.

Snape smoothed the letter flat on the desk and read it again. Surely this is not a prank. Someone - someone he knows quite well, by the sounds of things - is declaring her love for him through the medium of letters.

'How bizarre,' he said to the empty office, and then remembered Lupin would need his Wolfsbane in the next couple of days, and that he ought to start making it. He shoved the letter amongst the papers, determined not to think about it more than he absolutely had to, and got brewing.

A couple of days later, as he put the finishing touches to the potion that stopped the werewolf rampaging around the castle each month, the brown owl arrived again.

It landed on the windowsill and hooted. It seemed quite friendly. He put his ladle down carefully, turned down the flame under the cauldron with a swoop of his wand, and went to greet the owl.

A couple of minutes later, the owl was flying off into the gloaming crunching an owl nut that he had found luckily in a pocket and he was reading the latest instalment of the strange person's declaration of love with an eagerness that he would have denied.

I hope that you were expecting this letter now. One may be a one off, but two seems like the start of something. And of course three begins to look like a definite pattern. I cannot say how long this will continue, but now I have started, I find I quite like it.

Do you like it, I wonder? I have no way of knowing. You are so very practised at appearing inscrutable. I should say that even were I to be present when you read one of these letters I could not tell how you felt about it. It is something that you are proud of, I should think.

I think I said last time that I wished I had a different object of my affections. That was true, though perhaps impolite. But you must see that? I never know what you're thinking. It makes loving you quite frightening at times.

One of the things I am most frightened of is you finding out who I am. You are far braver than I have ever been, but then, you are far braver than almost anyone.

The author was right about that, no matter how unreadable he might find Snape. He wondered briefly why he did not feel quite so pleased with himself for hiding the advent of these confusing letters any more. The last sentence though… he felt a little surge in his throat and realised he was pleased, that someone had recognised the sacrifices he had made. But who on earth?

He thought for a moment, then tapped the paper with his wand and muttered 'Specialis Revelio'. Nothing, unsurprisingly. 'Pia pium.' Nothing. 'Enigmato'. Nothing. 'De Arcanum.' Nothing. He drummed his fingers thoughtfully on the workbench, then jumped as someone knocked on the door.

It was a polite knock.

He stuffed the letter hastily in the pocket of his robes, put on his best sneer, and opened the door with his wand.

'Lupin.'

'Hello Severus,' said the werewolf as he crossed the room. 'How are you?'

Snape did not reply, preferred to demonstrate with his expression what he thought of such a foolish line of questioning.

'I've come for the potion,' said Lupin, who did not seem at all nonplussed by Snape's rudeness.

'What else?'

Snape ladled a good amount into a stray goblet and shoved it across the bench to Lupin, who picked it up and knocked it back, replacing the goblet and grimacing horribly.

'Thank you very much. It's very good of you, doing this for me. I only wish there was some way I could repay you.'

Snape shrugged uncomfortably.

'Unfortunately for you, there is no skill or item that you possess which could come any way towards compensating me.'

'No, of course. Sorry to disappoint you.'

The werewolf turned and left the room, closing the door carefully after him, and Snape turned back to his intriguing letter.

Over the next couple of days, Snape exercised his considerable ingenuity to finding out who was writing to him so secretly. He had brewed all the potions he could think of that might possibly reveal secrets, but it had just left him with soggy and stained letters. He dried them carefully in his airing cupboard before trying another battery of spells and charms but, apart from inadvertently setting one of them on fire with a spark from his wand when he lost his temper for the twenty-third time, nothing happened.

'In the name of all that's magical!' he shouted as he doused the flames.

He did not stop to think why exactly he was so intent on finding the letters' author. Part of it was pride, of course, that he did not care to be out-magicked by someone else. Part of it was curiosity. Who found him so attractive that they would write letters and take such cautions to remain an enigma? And part of it… well, he wondered if there was any possibility that he could feel the same way. He had been alone for so very long…

When the next letter arrived, he petted the brown owl and, to his surprise, found his fingers were quivering with excitement as he untied the letter.

I do not know why I continue to do this. It is utterly pointless. No doubt these letters are now ashes in the grate of your fire. And by remaining anonymous, I ensure that the tiny chance I have of finding happiness with you does not change. If anything, it probably worsens. Who could love such a coward?

But oh, Severus, now I have started, I cannot stop.

I love the fire in your eyes when you come across a problem that intrigues you (how I hope these letters light such a fire). I love your bravery - but then you already know that. I love the skill of your hands, chopping and stirring, creating such incredible potions. I love the quickness of your mind. I love the rare, so rare, occasions when you find something that amuses you and your lips twitch like you are holding back a wave of laughter. I would love to hear you laugh. I would love to make you laugh. I would love you to touch me with those clever hands. I would love to find out if that tongue is really so sharp.

Snape sucked in a gasp of air. Things had taken an interesting turn. He hunted around for a quill and a spare piece of parchment and started to make a list.

The next few days, whenever he had a moment and could be sure of not being overlooked, Snape pulled out the parchment and worked on it, added names and comments as he saw fit.

Potentials (in no particular order)

-Students. Please the gods, no. Maybe Harriet Dax or Hermione Granger.
-Bay Hooch. Possible, but not her usual style. Would have been more blunt. Sporty type. Also I understood she preferred the company of women, specifically…
-Artemis Sinistra. See above. However, more likely to have written like that. We have a civil relationship (rare).
-Pomona Sprout. Prefers the company of flora to humans. Does not appear to have much use for my opinions on growing. Would send me a useful plant, not a letter.
-Poppy Pomfrey Just seems extraordinarily unlikely. However, I cannot write her off completely.
-Minerva McGonagall. Entirely wrong. Also, wrong house, and clearly has been nurturing a passion for the Headmaster for years.
-Sybil Trelawney. Incapable of writing direct and attractive prose. Appears to prefer Lupin.
-Charity Burbage. Unable to fall in love with a former follower of the Dark Lord. However the letters appear to regret the choice of me. A distinct possibility.
-Septima Vector. Perhaps. Sensible woman, though.

He reached the end of the list for the hundredth time and chewed thoughtfully on his quill. Although he had never met another wizard with the same propinquities as himself, he had acknowledged something like them on his list already. He dipped the quill in the bottle of ink.

-Rubeus Hagrid. Extremely unlikely to write such a letter.
-Filius Flitwick. Has a way with words. Potential.
-The Headmaster. A thousand times no.
-Remus Lupin. Probably capable of stringing a coherent sentence together when not forced to speak it aloud. Still besotted with Black ?his lover?
-Argus Filch.

He shuddered.

Of course, there were others, outside the castle. He had the feeling that this correspondent was within Hogwarts, but he was loathe to rely on instinct with no evidence to back it up. He did not have many acquaintances who he saw at all regularly…

-Lucius. History... However he surely only loves himself.
-Narcissa. Ditto.
-Rosmerta. I cannot imagine in what universe she would be attracted to me. She prefers brawny and brainless. However, friendly. That is her job.
-Master Dickens from the Hogwarts bookshop. Hates me, ancient.

Likelies

-Burbage
-Vector
-Poppy
-Flitwick
?Rosmerta

He chewed the quill again. A brief enough list to do some detecting, perhaps. He looked at the names again then looked up with a curl to his lip. Of course, there was always the possibility it was someone entirely outside Hogwarts. He did not venture out very often, but someone potentially unhinged enough to write such things to him could easily fancy themselves in love after one chance meeting.

Dear Severus,

I feel fairly safe that you have not yet discovered my identity. I wonder what I hope to gain from keeping my name a secret. Perhaps I hope I can inveigle my way past your defences on the page, and that once you see me face to face you will be less inclined to hex me into a heap of smoking robes. Silly, I suppose, but I can't think of any other way.

You would not be the man you are, the man I love, if you could easily and happily trust me, but all the same I am afraid of your reaction to me. I think you will be disappointed if you ever find out who I am, and that's leaving aside the possibility that you cherish some feeling for someone and you hope that they are your correspondent. I am sorry, if that is the case. I did not mean for this to hurt you. I want rather to protect you from hurt, if you can believe that. I know you don't need protecting, but that doesn't stop me wanting.

Thank you for being kind to the owl. She seems to like taking my letters to you.

When Snape looked up, he was almost shocked to find himself alone in his dark office. While he had read the letter he had felt as though someone was near, someone who loved him, and he was surprised to find himself bereft. He folded the letter up and put it with the others, now tied together in a bundle and hidden in a heavily charmed drawer in his desk. Then he pulled out his list.

Burbage, Vector, Poppy, Flitwick.

Who would want to protect him, he wondered. Poppy maybe, and Flitwick seemed absurdly fond of him…

For the first time, he allowed himself to wonder who it was that he actually wanted the writer to be, and the result made his hand shake so much that he screwed the list up and stuffed it in his pocket. He left his gloomy office and did some impromptu patrolling of the lantern-lit corridors. His point-taking that night was so ferocious that even the Slytherin hourglass was looking depleted the next morning.