Having left the Headmaster's office I spent several hours in the Library, of course, making my calculations hidden behind a massive Arithmancy book that was, very usefully, keeping everyone away from me.

I fully intended to go back and reverse what I had done in the hopes that it would return things to the way they should be and that I had learnt enough about the experience to be able to help Harry with what he needed to do in the future, despite still being none the wiser about what that was going be.

However, throughout that time, running alongside my desire to do what I knew I had to do my thoughts kept returning to my beloved Severus — my not-so-handsome-but-beautiful-on-the-inside boy with his dark shining eyes and his soft words and tender kisses — and I didn't want to lose him.

I didn't want to remember him as something that had no longer happened. I didn't want him turned into a case of wishful thinking. Although I had previously never had any interest in Severus when he was Professor Snape, except for how he fitted into Harry's story, knowing now what a bitch Lily had been to him during his time at school I desperately wanted his life to turn out better than it had in the original timeline.

This desire wasn't helped by him coming to find me in the Library. The two of us stared at each other awkwardly, neither of us knowing what to say or who should go first. Eventually, as the teacher, Severus seemed to find his voice.

'Will you come to my office, Miss Granger? I'd like to speak to you in private for a few minutes before you set out on your mission for Professor Dumbledore.'

I nodded, still not able to say anything, then packed away the books before following him out of the Library and down to his office in the dungeons, all the while wondering what we were going to say to each other — what we could say to each other after so many years.

'You must have been here all these years but it's as if I never noticed you until tonight,' Severus said once we were sitting in his office. 'I have to admit that it was something of a shock to see you — still looking like that.' He indicated my school uniform.

'I was and I wasn't,' I tried to explain. 'While I was changing the timeline in 1978 I didn't exist here any longer, but as soon as I returned to 1997 I had always been here.' I stopped for a moment, then added, 'I assume Professor Dumbledore did explain to you what I did?'

Severus considered this question for a few seconds before indicating with a curt nod that the Headmaster had talked to him.

'He wasn't really explicit about it but I understand the gist is that you went back in time to attempt to stop He-Who-Must-Not-Be-Named from ascending and you made things worse.'

There was that nasty, sarcastic edge to his voice that I remembered from so many Potions lessons at his hands in my own timeline. So, Severus might have become a nicer person in this timeline but he still had the potential to be a snarky bastard when he wanted to be.

I was blushing furiously as I retorted, 'You make it sound like I made things worse deliberately but I was honestly trying to make things better for everyone. How was I supposed to know that you had to become a Death Eater or that the bloody prophecy was so important?'

'I was supposed to become a Death Eater?' Severus looked at me in astonishment, then he frowned. 'You mentioned a prophecy to me the day you left. But there was no prophecy. It always made me wonder what you were talking about.'

I stared back at him, tears in my eyes, as I nodded. 'In the original timeline, you went to work for Voldemort because of what Lily did to you.' I looked surprised when he flinched at the word Voldemort. 'It was your way of getting revenge on her and the Marauders, I suppose. There was a prophecy — is a prophecy — but because you didn't become a Death Eater you didn't get to hear it and tell You-Know-Who about it so he never took action.'

I shook my head sadly. 'But You-Know-Who hearing about the prophecy is what created the one person in the world who could defeat him. That never happened, and the Order of the Phoenix was never strong enough to crush him on their own as they didn't have a spy — you — in his camp.

'Instead of being all but defeated when he attacked Harry, giving the Order more than a decade to prepare for his return, the Dark Lord has steadily risen to power and consolidated it, and now no one can topple him. There is no Chosen One to defeat him. He was never created.'

'Harry. Are you saying Harry Potter is this 'Chosen One' in the original timeline?' Severus asked interestedly.

'Yes. The prophecy that you related to Vol — You-Know-Who — told him that he would be defeated by a child born at the end of July to parents who had thrice defied him. Lily and James had always opposed him and their son was born on the 31 July. He decided it was them and went to kill them, on Halloween in 1981. Lily died defending Harry and in doing so created strong ancient magic that turned him into the Chosen One, and her death had you defecting to become a spy for the Order of the Phoenix.'

'By going back in time I hoped to stop the prophecy from happening, to stop Lily and James from dying. I thought that an Order that still contained them and the other Marauders — and hopefully you, too — would be strong enough to defeat You-Know-Who and we would never need a Chosen One, and Harry would still have his parents — that there would never be a second wizarding war. Unfortunately, it was a flawed plan because I didn't know enough about the prophecy and severely underestimated You-Know-Who's strength.

'Now I have to go back and put things right so that the true timeline can re-establish itself,' I concluded, sounding maudlin.

'You becoming my girlfriend changed things,' Severus said quietly after a couple of minutes of silence had passed between us. 'When you left so suddenly I was devastated. I couldn't understand why because you wouldn't explain, apart from that cryptic garbage about the prophecy, and you hadn't told anyone else you were going.

'It was actually the turning point in my relationship with the Marauders. Although we weren't mates by any stretch of the imagination, they were far more sympathetic towards me in the aftermath of your departure than I expected. The enmity disappeared almost overnight and when we left school we did so as comrades, all joining the Order of the Phoenix to fight against He-Who-Must-Not-Be-Named.'

'It wasn't enough, though,' I told him unhappily. 'I ruined everything when I stepped in to stop Lily and the Marauders from treating you so badly. It was the bitterness that was created in you that was the catalyst for everything that came after and was the whole reason there was a Chosen One who could fight Vol — You-Know-Who.'

'But surely Dumbledore had a plan?' Severus asked.

I sighed. 'Professor Dumbledore's plan has always been for Harry to be the Chosen One. Even he could never defeat Vol — You-Know-Who, and I think something happened to him after their last battle that has depleted his energy considerably. My Professor Dumbledore seems a noticeably older man these days, and he damaged his hand — spell damage, I think.'

'So Dumbledore isn't the answer, then — although our one is still perfectly healthy and hasn't recently been in a fight with He-Who-Must-Not-Be-Named. But if this prophecy exists, perhaps it could be triggered now,' Severus suggested.

I shook my head. 'It's too late for that prophecy now, Severus. I've seen your Harry and he could never take on the mantle — he's far too scared. It's not his fault, it's the way he's been brought up. In the original timeline, he did nothing but fight his whole life. After his parents' death, he was left to be brought up by Muggles and they were really horrible to him. It was a struggle for him to even survive.

'Then at school, we had to face . . . well, we had to face you and your hatred for Harry because of James . . . and Lily, too, I guess . . . and he did all sorts of things to make himself stronger. He fought the badly depleted Vol — You-Know-Who almost every year in some guise or other, and always beat him back.

'We even taught ourselves real defensive magic when the Ministry of Magic stepped in to stop us from casting actual spells in class. His whole life was spent preparing for him to be the Chosen One, but this Harry could never do that. He can't even cast a defensive spell, let alone fight the strongest wizard who ever lived.'

I could tell from the expression on Severus' face that he understood what I was saying; that I was right: there was nothing that could be done in the current timeline to make things better. I had no choice but to go back and undo the damage I had done.

He was still staring at me, every bit as avidly as I was staring at him. I was taking in the changes the years had wrought in him, still able to see the boy that I was so in love with beneath the older man's countenance. It hurt me being this close to him and not being able to hold and kiss him the way we had done only hours earlier, as far as I was concerned, although of course, it had been almost two decades before for Severus.

'You have no idea how I felt when I saw you again,' he said quietly. 'It was almost as if we were back in that corridor; as if you hadn't left me. I had to remind myself that it had been years and that I wasn't a teenager any longer.'

'It had only been minutes for me,' I told him. 'I literally left you in that corridor and then went straight to the place where I had Time-Turned. When I saw you in the Great Hall it had only been about ten minutes since I last saw you. It was pure agony for me.'

'Seeing me so old?' Severus asked.

I shook my head, fighting the tears that were threatening. 'Seeing you at all. I love you so much, Sev, and I so didn't want to leave you, but I had no choice — and then there you were, the one I had given everything to but you had moved on, had lived your life without me, and suddenly I had to become your student again.

'It was hard seeing you, and now it's harder still because I have to go back again and undo everything that was between us. I have to make sure it never happens, that time goes back to its original path . . . and I really don't want to. I don't want to lose you and what we shared. I don't want to erase you from my life. I love you!'

I was sobbing now, big fat teardrops running down my face as I admitted my true and most immediate feelings to a poor, bemused Potions Master who had long since recovered from any desire he may have held for me. But that was the problem: it wasn't in the past for me. I was still living it and it hurt like hell.

I tried to stop my tears, wiping my face with a handkerchief which did nothing but get wet, but then Severus was out of his chair and around the desk, wrapping his arms around me and holding me tightly as I wept. It felt so good to be in his arms again and I wished I could figure out a way to stop time now, forever, so he would never let me go.

'I spent years wishing you would come back,' he admitted, his voice a soft burr in my ear as he cuddled me. 'I was in love with you, too, Hermione. I would have done anything to see you again, even if it was just once.'

He gave a dark chuckle. 'I even considered joining He-Who-Must-Not-Be-Named for a short time, in case he had some Dark magic that would allow me to get you back. But you had disappeared without a trace, almost as if you had never existed in the first place. There was no point in searching for a phantom, however real you had seemed when we were in bed.'

I felt my body tingle at his mention of our time together, making love, and knew I was blushing, still unable to believe that I had so easily given myself to him when there had never been any chance of a happy outcome for us.

'You were everything I wanted . . . everything I needed, but eventually I came to believe that you had been sent for a purpose and I wasn't meant to see you again. I have to admit that part of me wishes I hadn't seen you again,' he continued.

'I'm sorry, Sev,' I said sincerely. 'I never meant to hurt you.'

'I know.' His voice was surprisingly stoic and accepting. 'But now you're here, so what do we do now?'

'You know I can't stay. I have to go back, have to reset the timeline.' I know I sounded miserable because I felt sick at the thought of what I was going to have to do.

'Do you have to go immediately?' Severus asked, his voice subtly more seductive. He was stroking my back and the small movements were sending tingles throughout my body.

'We can't—' I said.

Severus kissed me, cutting off whatever I was going to say next, and to be honest I have no idea what that was. Joy, desire and a million other emotions overwhelmed me as I kissed him back just as fervently, wishing for the second time that night that time would freeze and keep us in this moment of bliss forever.

It didn't, of course, but as had always been the case a second kiss followed the first, and then a third, by which time I was out of the chair and being carried towards a little-noticed door and through to Severus' private quarters.

Once again I have no intention of going into details about what occurred when we reached Severus' delightfully big bed; let's just say we may have recreated some of our finer moments from the visits to the Room of Requirement and leave it at that. By the end of it, I knew I would forever be in love with Severus Snape, whatever timeline we were in and however old he was.

Obviously, this gave me something of a problem.

I couldn't stay here in this current time, as pleasant as it was, with Severus older and more experienced, even if only because I had promised Professor Dumbledore that I would return to 1978 and re-manipulate the timeline. I can assure you this was the only reason I wasn't just hunkering down and making the best of the shitty timeline I had created, with my beautiful reinstated lover at my side.

If I did what I had promised I would lose Severus again, and this time it would be forever. The Professor Snape in my timeline (never Severus) couldn't stand me; I could imagine the scorn with which he would greet any attempt by me to initiate something between us.

Of course, I knew this was my punishment for daring to play god with a whole world, but it seemed so unfair that I had to return to the original timeline, which was still going to need dealing with, and that I would be stuck with the memories of Severus and the love we had shared — now in two different timelines — and would have to live with snarky Professor Snape, knowing that he would never have the faintest idea that we had once been in love with each other. It was going to be a rough punishment, and one I wasn't sure I deserved.

But I had no other choice. The wizarding world needed Harry to be the Chosen One, Severus had to join the Death Eaters and hear the prophecy, and I would get to spend the rest of my life wondering what might have happened had Severus and I had the chance to live our lives together as a couple — from either timeline.

I kissed Severus once more, enjoying for the last time his arms around me before slipping from the bed to retrieve my clothes. Although I wasn't at all happy about what I had to do I was ready to do it. There was no point in putting it off any longer otherwise I would only feel worse about having to leave Severus. It was already tearing me apart.

With a final fond farewell, I made my way back out of the school to find my now hated Time-Turner spot.

Of course, I didn't do what Professor Dumbledore had told me to do.

I'm sure you've realised that by now because of the way I'm writing to you at the moment. If I had, I would have returned to Hogwarts in 1997 and followed whatever plan the universe had in store for us. I might even have ended up going out with Ron eventually, assuming we survived Harry's battle with Voldemort; because we would have been there to support him, right until the very end.

Perhaps Professor Snape would have been so unpleasant to me over the following years that I would have managed to forget all about the love we once shared, and life would have gone on in the way it was always meant to, with no one any the wiser that I had ever tried to change things.

But I just couldn't do it.

It was hard enough to know that I would have to return to 1978 and not interact with Severus in any way, to watch him get bullied and teased without stepping in to help. But having made love to him in 1997 as well as 1978 made it impossible. I was so in love with Severus that I couldn't let him go. I would return to 1978, just as I had promised the Headmaster I would, but I was going to have to find another way to manipulate the timeline because I was not prepared to lose Severus.

And so I used that bloody Time-Turner one last time; not to go to a couple of days after my original arrival in 1978 but back to the day I left.

I had made my decision and now I had to go all out to make sure that this timeline, however, good or bad, would do what it needed to do: Severus would hear the prophecy; Harry would become the Chosen One, and crucially, his parents weren't going to die. Furthermore, I would be there to guide Harry through his life and help him with everything he needed to know to defeat the Dark Lord.