Disclaimer: I do not own these two fantastic characters, and I am more than happy that I don't so I can play to my heart's content. The title is from the well known poem 'To His Coy Mistress' – Andrew Marvell. Had we but world enough, and time, This coyness, Lady, were no crime / We would sit down and think which way / To walk and pass our long love's day.

A/N: Here we are. I caved. Below is my nod to the obligatory story about the conundrum that is time. Thank you to Lystan, the Thorin to my Snape ;-)

Do you trust me, dear reader? Trust that I will give you a HEA for our favourite pairing, but also trust that, just for the reading of this story, you can let go of everything that is correct about time. In our little AU universe, it's all flipped on its head. This is inspired heavily by the S. Korean film 'Il Mare', which you might recognise was also made into a Western film named 'The Lake House'. I'd love to hear your theories and thoughts, so be sure to let me know what you think. More on the time difference will become clear in the coming chapters and I promise to give you an explanation that is as plausible as I can get it ;-) Let's begin!

Chapter One

Time is nothing.

Audrey Niffenegger

1997

The Headmaster's office was exactly the same. Nothing had changed – had he really expected that it would have? Strange little instruments still whirled and twirled in towering bookshelves, and there was even a quill resting against an inkpot on the desk, as if the last inhabitant had simply left for a sojourn to the staff room, rather than falling to his death from the Astronomy Tower.

Severus stared at the desk and wiped a clammy, shaking hand over his face. When his eyes opened, the scene was unchanged; he was still standing in front of Albus' desk, and he was still about to walk around it and assume the position of the man he had murdered. Killed, he reminded himself. Yes, Albus had been very persuasive that his task was to kill him, not to murder. To grant a dying man one last act of mercy, at said dying man's own request.

Severus was more inclined to believe that it was a cop out. Who was Albus fucking Dumbledore to say that Severus' soul could withstand pointing a wand at someone and murdering them? He hadn't ever killed before – not like that night, at point blank and staring into his victim's eyes. Severus had knowingly killed, yes, but as a truly merciful act: for a mother so she would not watch her tiny little child writhing under the insane Bellatrix's wand before having to submit to Greyback's never ending thirst for unwilling flesh. The green light bursting from his wand had been easy to conjure, then. There were other instances, other times when he had done similar things; all were infinitely more worthy of his self-hatred than the wizard who once sat in the chair that he was walking towards now.

He sank down into it with a sigh. Albus had tied up all of Severus' guilty thoughts and self-deprecation, and presented it back with an unbending order. And then, as if Severus had ever had a choice about it, the old goat had framed it as a question – like there was a chance that he could decline!

Severus slammed his hands onto the desk. Would it never end? Perhaps the better question was: would it ever end for him?

He was tired. Oh, was he tired. He let his head fall into his hands and closed his eyes again, breathing in slowly as he tried to fight a wave of exhaustion. There was simply no time to be tired – the Carrows would be arriving tomorrow morning, though the obscenely disgusting pair would more than likely show their faces in the afternoon from sleeping off whatever revolting acts they committed tonight.

His own task for tonight was not conducive to a good night's rest. Severus had to become acquainted with his new office, search out all the little nooks and crannies that Albus had used before. No information could get into enemy hands and the old man had become so nervous and jittery by the end, thanks to his own stupidity of course, that only Merlin knew whether he'd thought it might be fit to stash things in here.

Severus wasn't exactly sure what he might find – Order secrets had already been passed to Minerva and Kingsley, some even to himself, but Albus had not been in his right mind. It was possible that he may have left hints somewhere for Potter. Granger, Severus corrected with a roll of his eyes. At some point, if he survived (which he would not), he should find a way to thank the girl. He had slept easier once he'd found out that Potter had taken her with him – sod the Weasley grunt, it was Granger that would be able to make sure they had the best chance at succeeding.

Severus began the search, deciding to start with the desk. He opened each drawer furiously, shoving his hands to the very backs and then repeating the gesture with his wand, seeking for clues. There was no end to the secret compartments – he found some while crouched under the desk, then while lying under it like a Muggle mechanic. There were more hidden in the drawers, and the entire top of the desk could be pushed up to show another layer of storage.

There was parchment everywhere. Normally a tidy man, Severus grumbled as he rifled through sheet after sheet, tossing almost everything into the fire. Nothing. But there had to be something here, surely. Albus barely left his desk – if Severus was going to find anything, he'd find it here, wouldn't he?

Ultimately, he had hoped that Albus' memories would be stored here. It was a fool's hope, but he couldn't stop wishing that the old man might have made some sort of plan that didn't involve sending Severus to the wolves. For that was where he would go on the odd chance that the Dark Lord didn't kill him first. If they did manage to win the war, then he would still be the man that killed the leader of the Light. Never mind that he was given no choice – never mind that Albus was almost dead anyway. Never mind the fact that it destroyed him to know what he had done.

But he found nothing. In a fit of rage, Severus upended the desk and watched its contents tumble to the floor, some breaking and sending shards of glass scattering over the marble tiles and crimson rug. It was almost beautiful, the chaos of it all. It made sense, which made him think that perhaps he'd drunk enough whiskey for the night.

He shrugged out of his robes and left them hanging over the back of the chair. In another life, if this truly was his rightful office, he would've sent the robes for cleaning and worn them with pride. Now, they stank of alcohol and cigarettes and he didn't care one fucking bit.

Sod appearances. He was playing his part, after all; the greasy dungeon bat, the hook nosed git. The traitor.

He strode to the stairs that led to the Headmaster's private quarters and ascended them two at a time. At the top, he turned to face all of the portraits. All eyes were trained on him, most with revulsion but some with understanding, and an emotion that he suspected was pity. He hated pity.

One look at Dumbledore sent him growling with anger. The goat was asleep, looking as peaceful as the geriatric sod that he'd become in the end.

"Well," said Severus grandly, "good night, you lot of fucking halfwits."

That ought to do it. As if on cue, the portraits gasped and huffed, and most disappeared to annoy different places in the castle. Job done, he turned on his heel and stalked into the sitting room that any other man would have been glad to have. For Severus, the opulence and soft, comfortable couches in front of the fire merely served to remind him of what he'd had to do to get here. That was enough to put him off the whole thing. He left the room quickly, walking through it to reach the bedchamber. Ignoring the huge bed, he pulled off the rest of his clothes and stepped into the shower, taking one small indulgence of standing under the searing hot spray for as long as his skin could handle it.

A tumbler of port awaited him; "Headmaster's finest!" a bubbling house-elf assured him.

Severus stopped counting after the eighth drink. There was nothing that he wanted to remember – only the reminder of the Carrows arrival had him passing on another glass. He let himself fall back onto the bed naked, glad for the fire in the corner of the room that made the room warm and comfortable; as comfortable as a monster was likely to get, anyhow.

He tossed and turned, looking above him at the canopy of the bed, charmed long ago to mimic the roof of the Great Hall with its stars and planets. There was something, some little niggling thing in his mind that refused to let him sleep. He sat up and looked about him – he hadn't even started looking through the sitting room yet, the bedroom would be left for another day entirely.

Yet instinct, if he could call it that, led him to the bedside table. An obvious hiding place, he thought, and would have dismissed it entirely if it wasn't for the plain folded over sheet of parchment sitting in plain view inside the top drawer. Frowning, Severus poked his wand at the parchment – he couldn't discern any curses, nor any other residual magic, though that did not mean that it was harmless. It could be innocent though, he mused… left in plain sight… an obvious hiding place for someone who left everything else in fake portraits and hidden compartments.

He muttered a spell and watched as the paper floated over onto the golden comforter then settled down onto it. It looked fresh, as if it had just been folded yesterday, but Severus was sure that no one had stepped into the office since he'd rid it of its master. He waved his wand around the room; sure enough, there were only faint traces of magical scents and all of those came from the old Headmaster himself.

Could it be? His heart sped up at the idea that Albus may have cared enough to leave him proper instructions after all. Very carefully, he nudged the paper wide open with his wand, eyes running over the neat writing that seemed strangely familiar, though it did not resemble the author that he had been hoping for.

What on earth is this? Severus reached for his thin glasses on the other table, shoved them unceremoniously onto the end of his nose and leant forward again to re-examine the letter until he fell back onto the pillows with a mouth that gaped open wider at each second.

'Dear Sir or Madam,' the letter began, causing him to scoff immediately. The old fool wasn't that senile and everyone knew who was going to be assuming his office after him. What the hell was this writer playing at?

'I am writing with a matter that may not seem to carry much importance to you, but I hope that you will take the time to read it and give appropriate attention to its contents.'

"Either you have a death wish, or you're a Gryffindor," he mumbled under his breath, sure that the students had somehow managed to penetrate the wards and place it there. Would they ever learn? Of course, he didn't want them to – it was part of the 'Master Plan' after all. Yet the brats never opened their eyes, never bothered to look beyond the surface. Here, it seemed, was just another lot of supporting evidence for his completely correct hypothesis. He read on.

'The role you have accepted is a vital one. You, Headmaster (though I confess to wishing that I am addressing this to a Headmistress) will lead your students out of the darkness and into the Light. You will make the school a symbol of hope for us, those that will return to you. Do not take such a mission lightly.'

Severus swallowed heavily as he read the remaining sentences. The person surely had a few screws loose… even more likely was that it was a trap. His heart sank; it would have been comforting to know that someone had cared enough to contact him. He made a mental note to again investigate the magical traces in the quarters when he woke, though he had no idea how one of the Dark Lord's lackeys had managed to get in here to place it.

'It is not my intention to be rude, Headmaster/Headmistress. But let me be clear: the man that you are replacing cannot be done so easily. He protected the students to his last breath, and you will be hard pressed to dedicate yourself with the same loyalty that he gave us. Try. That is all we ask of you.

We are counting on you; if you have any doubts, you will, of course, have seen all of the latest news about your predecessor. Read it. Understand the man whose quarters you now reside in, and know that he was the bravest man this school has ever had the honour of having lead it.

We are placing our hope in you, Headmaster/Headmistress.

Please – do not let us down.

H.

P.S I have tidied the office to ready it for you, and the personal effects of the Headmaster have been retained so as to be kept private. If you require anything, please contact Professor Minerva McGonagall. Unless you are Minerva – in that case, I knew it!'

"Definitely a trap," he said softly, scouring the letter. 'H'? Could they have been more obvious? Potter was far from Hogwarts at this point – how could any Death Eater even entertained the idea that he would fall for such a ruse? And mentioning Minerva? She'd gladly take his bollocks on a platter at this point, what a farce.

Severus read it for a fourth time and snorted, glad that at least the writer had probably gagged after writing so much about Albus. That was almost revenge enough.

He summoned a bottle of red ink from the desk and grabbed a quill, delighting in his self-appointed task. With a flourish, he drew a solid line over the entire letter then chuckled to himself as he penned a little reply that would show them who they were dealing with. Finally he charmed the handwriting to hide his own spidery script, replacing it with dull block letters.

/

'You are a fool. And if it is you that is responsible for the mayhem in the office, then your understanding of 'tidy' is damnably incorrect.'

/

He would address it further in the morning. Perhaps he could get Pettigrew punished once or twice – Merlin knew the rat deserved it a thousand times over. Shrugging, Severus shoved it back into the drawer, set his glasses on the other table then slid under the blankets.

The wind outside was blowing gently, and the roaring fires soothed him more than he would care to admit. Yet still he could not sleep; thoughts swum through his mind until he sat up again with a groan and measured out a dose of Dreamless Sleep, notching a stroke on the small pad of Muggle paper that he kept with it to monitor his usage. Again he stretched out for the bedside table, intending to place the remainder of the potion and paper in the drawer with the strange letter.

If he hadn't extinguished the lights and taken half a teaspoon into his mouth already, Severus would have seen the chilling lack of anything inside the drawer at all. He fell asleep quickly, his face slack and calm, completely unaware that the letter and his response had vanished.