‘You wish!’ Elton shaded in a whole lot of nothing on the map. ‘You go out there, and before long you’re going to be begging to eat a nice juicy locust.’

We spent the rest of the session wandering in the wilderness. It sounds dull, but sometimes focusing on the simple but necessary mechanics of life on the hard edge can be quite therapeutic. In place of orc hordes, vampires, and abominations, our enemies became hunger, thirst, and exposure. We concerned ourselves with food, water, and shelter, and for a city boy Elton seemed to know a lot about just how difficult those things are to acquire in a trackless waste.

‘Your ride’s here, Nick!’ Simon’s mum, yelling up the stairs with her usual gusto.

I swept my stuff into my bag, dodging questions about whether I’d make school in the week.

‘How you doing, Nick?’ Elton blocked my way as I tried to leave.

‘I’m fine.’ My eyes prickled. I’ve never been good at having people care about me.

He grinned and shook his head. ‘You’d say that if your leg had just fallen off. You ain’t fine, man. You’re in the shit and we all know it. But we’re gonna pull you out. You even got some crazy guy says he’s from the future to help. Probably put his robots on the case. But you ain’t fine, so don’t say it.’

‘OK.’ I struggled to keep my voice steady. ‘I’m not fine. I feel like I’m dying . . . Also, some bastard’s given my D&D character fading sickness.’

‘Better.’ He punched me on the shoulder and stepped aside. ‘Henri is twenty-one on Thursday. Party, Friday night. You’re coming. John and Simon, too. No excuses.’

‘Yes!’ John punched the air. Parties at the Arnots’ were a thing of legend, and Henri, Elton’s oldest and coolest brother, was enrolled at dance college where he was literally the only male student in his class. Which meant his guest list would be packed with female dancers.

‘I can’t.’ Simon shook his head.

‘Can and will,’ Elton replied firmly.

I glanced at Mia. She nodded, which I took to mean she was going. ‘See you tomorrow.’ She hadn’t forgotten our ‘date’ in the park. Me, myself, and Mia: our very curious trio.

John raised his eyebrows at Mia’s ‘tomorrow’ and I offered him a grin before lifting a hand in farewell and setting off down the stairs. ‘Later.’

Another week to our next session, another five days to the last chemo cycle of my first course, another six days to Henri’s party. My own wilderness stretching ahead of me. It might only be a week, but something told me that forty days and forty nights might not be enough to cross it.

CHAPTER 13

‘Hey.’

‘Hi.’ Mia was waiting for me at the gate we used on ‘vampire night’. Richmond Park stretched out behind green-painted iron railings, an uninspiring expanse of wet grass.

Mia shrugged away from the gatepost and came to walk with me, breath fogging the air. A light, annoying rain had started up, the super-fine kind that gets in your eyes and coats your face.

‘So.’ Mia kept close to my side. ‘This is kind of crazy.’

‘Very.’ I liked having her close. ‘I’m glad you decided to come.’

‘It’s not really the sort of thing you can just walk away from,’ she said.

‘No.’ I knew that Demus had helped her out with the money, but if she was like me then the real reason she was here was that, after the initial shock of it had sent her running from the car, the mystery of it niggled at her. And an itch like that has to be scratched. ‘I want to hear what he says.’

‘If it’s true . . . what he says . . .’

‘It makes you wonder what you can be sure of anymore. If anything is certain. What really matters.’

‘Yes.’ Mia stopped and looked up at me. ‘Exactly. All those things.’

‘I’m good with questions. Answers . . .’ I shrugged. ‘No sign of Rust since . . . ?’

‘No.’

We started walking again. Nobody I knew had seen Rust since he got cut. It made me uneasy. Like a shark’s fin vanishing beneath the waves.

‘So, do you think Simon will come to the party?’ Mia asked.

‘No.’ I didn’t think I would either. The thought of a party both thrilled and appalled me.

‘Why?’

‘I can think of about a thousand reasons!’ The Arnots’ parties were a thing of legend and this would be my first chance to experience one for myself. But I was hardly at my best.

‘Name one.’

Rather than choose one of Simon’s many reasons, I decided to offer up my own worst fear. ‘Dancing, for a start.’

‘Dancing?’ Mia laughed. ‘It’s not like you’re expected to do the waltz and the foxtrot, or do it in squares like a barn dance. It’s just . . . you know . . . dancing! Like on Top of the Pops, but with less lamé and glitter.’

‘He won’t do it. He can’t.’ Top of the Pops was another of my mother’s guilty TV pleasures, and I’d been watching the audience bounce around to the top twenty for years. But I still had no idea how it worked, and no desire to demonstrate that fact in front of Mia, with a backdrop of Henri’s dance school hotties showing everyone how to really do it.

‘Nonsense. Get over to Simon’s during the week and make him have a go. It’s as easy as climbing stairs. Move around a bit in time to the beat and that’s all there is to it. You don’t have to do anything fancy.’

‘Yeah. I . . . uh. I’ll tell him.’

‘Don’t tell him. Go there. Make him have a go, then make him come. Seriously.’ Her hand brushed mine. It could have been an accident. ‘It would be stupid if he didn’t go.’

Demus was waiting on the bench, wrapped in a heavy coat. Black, unmoving, and ominous.

‘He is like that vampire,’ Mia muttered as we approached.

‘Sorry?’

‘In the game,’ she said. ‘Sucking away memories.’

She had a point. In D&D a vampire’s touch robbed you of experience. It took away what you’d learned and left you as a shadow of what you were. I didn’t like to think of myself in those terms. I hoped Demus had an explanation that showed myself to me in a better light than that. So far, as a mirror he had proved to be very troubling.

Demus glanced up when we drew near, my own worries echoed on his brow. He looked tired and the rain beaded on his baldness.

Mia sat at the far end of the bench. I sat between them.

‘How do you know me?’ Mia’s first question.

Demus leaned forward to look at her across me. ‘I’m no expert, but I’m pretty sure it isn’t good for anyone to know too much about their future. So, let’s forget the how, and leave it at the fact that I do know you and I want to help.’

‘OK . . . Why do you want to take my memories?’ Mia wasn’t wasting time. John had wanted to know if they had hover-boards in the future and what Mars was like. Mia, sensibly, was all about Mia.

‘Good question. I don’t want to actually take your memories. I just want to copy them. But the “why” is still valid.’ Demus rested his elbows on his knees, chin in hands. ‘Years from now, you have a very serious accident. You have a brain injury. The injury is repaired using stem cells, but that’s like rebuilding the library, putting the shelves back up, and putting new books on the shelves . . . Only, all those books are blank.’

Mia managed to look horrified and sceptical at the same time. ‘What kind of—’

‘It doesn’t matter. What matters is that you’re now old enough that the architecture of your brain is fixed in place. A record of your memories now, along with updates made every five or ten years until the accident, would allow those memories to be reinstated into your repaired brain, restoring everything you’ve lost.’

‘Why . . .’ Mia frowned furiously. ‘Why . . . don’t you just tell me what the accident is, and then I can avoid it?’

‘Ah. Well. There it becomes complicated. Nick’s already told you about how quantum mechanics reveals to us that every action splits the universe into a great many new versions where each possible result plays out. The simplest answer to your question is that in my timeline I didn’t tell you what the accident was. So if I were to tell you now, then we wouldn’t be in my timeline anymore. And if we’re not in my timeline then the accident may not even happen, or my advice on avoiding it might make it happen. And yes, one of the multiverse’s infinity of Mias may avoid that particular harm, but the Mia I know, the one that’s my friend, will still be a helpless shell of what she was, and my efforts to restore her will have failed. I can’t change my past. I can’t change that part of your future that is already in my past. But I can change my future, and you are in it.’

‘I think my head’s going to explode,’ Mia said.

‘Well . . . if it did, it would save an awful lot of bother.’ Demus leaned back.

‘Why do you have two headbands?’ The question had been puzzling me all night.

Demus dug in his pocket and brought out a plastic rectangle large enough to cover his palm.

‘What is it?’ Mia reached across me to take it and he let her.