It's been nearly twenty years since I had a conversation that would change my life. Twenty years since that boy came into my office and told me perhaps the most fantastical story I would hear all my life. A story that's stuck in my mind so clearly all of these years. Of course, I didn't believe it then; but now, after so many years, after the life that I've lived since that conversation, I cannot help but think back on that day with guilt and regret, and now finally fear.I was a headmaster then, at a Primary school in Northamptonshire, about six years away from retiring. A boy called Chris was sent into my office for locking two other students in the tech cupboard, a room where we kept equipment for the science lessons taught at the school. I knew of him, knew he was a good student; he'd once shared some work in a school assembly. He had always seemed to me quite bright and a little shy. Not so that day. He was making a great fuss, I remember, about being sent to see me."It's not right, this isn't right" he repeated over and over as Judy, his teacher, practically carried him in. She explained the situation to me and then left to get back to her class. I remember I sat silently staring at him from behind my desk, the stern look I reserved for such situations across my face. Again and again he said it:"This isn't right; it's not supposed to be like this."He looked odd; panicked and upset, though not in the way one would expect a ten year old to be on being sent to the headmaster's office. His eyes darted back and forth, as my own have many times when in bursts of rapid thought. Eventually I spoke over him."Christopher. This is very disappointing."I always used a full first name if I was giving a child a telling off, it sounds so much more serious. He took little notice and carried on repeating those same words, glancing this way and that, looking utterly confused."Christopher. Christopher. Look at me when I'm speaking. Christopher!"I remember I raised my voice almost to a shout as I said his name that last time, something I rarely did. His eyes snapped onto mine as he fell silent. I expected to see them gloss over, it's a dreadful thing to make a child cry, and so I began again in a calmer tone:"It's disappointing to have you sent-""Look, something's gone wrong somewhere. This isn't supposed to happen like this."I was shocked to be interrupted, but what startled me, what left me speechless for those few moments as he carried on, was the way he spoke. His voice was that of a young boy, to be sure, but as if under the control of someone far older. His enunciation was clear and precise, his tone somehow mature and serious."I just need to think for a moment, I can sort this out. I just need to think."His eyes went back to their darting to and fro. I had found my voice by now."I expect you to listen when I am talking to you young man. Do not interrupt me when I am speaking."His eyes fixed onto my own again and he spoke before I could continue."Sure, sure, Ok. Look, just give me five minutes to talk ok. Five minutes, that's all I'm asking."I'm not sure what made me do it; perhaps it was just the peculiarity of the whole situation so far. I sat back in my chair, took the pipe out of my top drawer and began to fill its end with tobacco, for one was still allowed to smoke indoors at this point in Britain."Five minutes."I lit the pipe and popped it into my mouth, gesturing that he sit down in a chair next to my desk, which he did, and let him speak."Ok, how do I... I've been here before, well not in this situation, but at this school, at this time; I've lived through this before. I've... have you ever seen the film Groundhog Day?"I shook me head."Ok, well... have you ever thought about going back in time, back to an earlier point, but as you are now? Travelling back to redo some of your life with the knowledge you have now? Well, that's what's happened to me, only... only I can't control it, and I can't stop it."He sat back a little further on the chair now, his face became grim as he looked out of a window across the room."I live life normally until my thirtieth birthday, and then I wake up a four year old, back in a house I haven't lived in for twenty four years. It sounds great, being young again, getting to go back and do things better... but it's a nightmare. The first time through, I showed off, I'd been a doctor of philosophy before I went back, I could do advanced mathematics, quote Shakespeare, play the piano; it was fun. I was a prodigy. But all the attention I got for me, got taken away from my younger brother. He wasn't the same brother I'd known before. And what was worse-"For the first time I saw his eyes become glazed and that piercing voice began to tremble."With so much time and effort put into me, my parents never had any more children. I had another brother and sister before, and suddenly they didn't exist, and it was because of me. I tried to tell people about what was going on, but it's a hard thing to prove. I'd tell them sports results that hadn't yet happened, warn them of natural disasters. When it became apparent that my predictions were right I was taken off to study. Drugged in a white walled room. You can't imagine how long twenty years can take in a padded cell..."He went silent for a moment, staring blankly out of the window. Then his eyes came back to me."But it happened again, I woke up one morning in my parent's house twenty six years younger. That second time round my parents had two more children, but they weren't the brother and sister I should have had. They were different, and the others were gone. Now if I try to get the first ones back I'm writing two other kids out of existence. You can't imagine the guilt..."He stood up then, and walked over to look at me over the desk, his head only just reaching over it so he could see me."Now I need your help. This is my twelfth time. I think if I can make it right, if I can keep everything the way it was supposed to be, maybe it'll go on. Maybe I won't have to keep doing this. I wasn't supposed to be sent here, you aren't supposed to talk to my mother about this. Look-"He grabbed a piece of paper and a pen and began scribbling something down. He handed it over after a moment. I forget what he had written exactly; some extremely complex looking mathematical proof."No ten year old should know this stuff."He grabbed another sheet and began furiously writing again. Names, dates, events, he passed it to me."I know it sounds crazy now, but just, just look. These are all things yet to come, you'll see, take it. Bet on the results, make some money. But please, don't interfere now, or again. You aren't supposed to be involved in this."I remember only a little of the conversation after that. It was ridiculous, what he was saying, how could I possibly believe it. I told him to stop talking such nonsense and sent him back to his class. I called his mother into my office when she came to collect him and told her about his misbehaving and this strange outburst. I kept his list though, I'm not sure why I did it, but I kept it, safely filed away in my study at home.I read in a paper a few years later that Chris had killed himself, around the time he told me his second brother should be born. I learnt later that his mother had miscarried. I worry now whether that was my doing. Maybe if I'd done as he asked things would have gone differently, who knows what effect that conversation with her had.It is now the afternoon of July 21st 2017, the day before Chris would be due to turn 30. Everything on the list that boy furiously scribbled down that day has happened. World cup victories, Hurricanes, the bombing of the twin towers over in the US. Everything just as he wrote it.But now my thoughts turn to tomorrow. What happens to me? What happens to my daughter, to my grandchildren? If everything goes back so he can live through it again, where do we go? Do we carry on without him? Or will we just never wake up; just disappear?I've lived a long life and I've done a great many things, but none haunt me so much as that conversation, and I've never felt as much dread as I do today. If we really do start over, I hope I listen the next time through.