‘Er . . . Hi.’ How she had come to produce a child like Simon I had no idea. Part of me wished my mother were more like Simon’s, but for that to work, I would have to be, too. We were neither of us people persons. But you’d have to uncoil our DNA to fix that.

‘Hey.’ Simon’s sister emerged from the kitchen, pursued by their cat, an enormous honey-coloured tom called Baggage. Sian was her mother’s child for sure: long hair, flower-patterned hippy dress, easy smile, twelve going on twenty, zero interest in her brother or his strange collection of friends.

Stair-rods held the carpet on the stairs in Simon’s house, and stylised tree patterns grew up the wallpaper, rising with you as you climbed. The place always had the same smell, a mix of lavender and sandalwood. I’d been coming there since I was four. We’d been in the same kindergarten, then the same primary school before both passing the exam for Maylert.

In the same period my parents had moved four times. Simon’s house felt more constant than my own. More like my home than my home did.

‘Here!’ Simon held up an inch-high painted figure, a warrior with a war-hammer. I was to look, not touch.

‘Sweet.’ He had shown me how to do the magic he did with the brush. I couldn’t do it.

On the table in his room half a dozen more figures stood ready for inspection beside a stack of rulebooks. A bright scattering of polyhedral dice and several incomplete map sheets completed the ensemble. People saw all that paraphernalia and their brains would dial in what they knew about games, board games with dice. Only this had monsters thrown in. Judgement made. But Dungeons & Dragons was never a board game. The figures and maps were just props. The rules weren’t even called rules; they were guidebooks, handbooks, manuals. It was all there to give just enough structure to our shared imagination that we could vanish into it for hours, unwinding a story as we went. A story unique to us, filled with our own wonders, ingenuity, and proxy bravery. And it was something that carried on week after week, building over years even, creating a shared history, bonds that weren’t ever going to appear across a Monopoly board or game of cards.

I went to my chair, finding for a moment that the room had grown distant, Simon’s voice faint. Déjà vu gripped me. My encounter with Ian Rust had managed to push out the thoughts that had been spiralling through my sleepless mind. The hand that reached forward to lift the gaming mat didn’t seem to be my own. The table before me became overlaid with my own hospital-vision of that same table the week before. My fingers remembered gripping the pen, grinding its point through the varnish, sending a message to myself . . . ‘Nothing!’ The wood lay smooth, undamaged.

‘What?’ Simon looked up from his monologue and blinked.

‘Did . . . Was there something written here? Did you turn the table around?’

Another blink. ‘No. What are you on about?’

‘Nothing.’ I let the mat flop back down. ‘Just . . . Nothing.’ It had seemed so real, but I guess that’s the point about hallucinations. William of Ockham wasn’t the first to point out, centuries ago, that the simplest answer is probably the right one, but he’s the most famous. I was in hospital being poisoned. Which was more likely, some weird kind of time travel, or drug-induced hallucination? I snorted at myself.

‘We miss something?’ John pushed the door open.

Elton followed in, already pulling his books from his bag. ‘I hope you guys were prayin’, cos I’m bringing the pain today!’ As the game master he was nominally in charge, designing the world we adventured in, but how we met those challenges was down to us.

Mia came in a second later, dark eyes ringed with black eyeliner, shooting me a look from beneath a black fringe. I blinked my surprise. One visit to the D&D table was unusual for any girl. Coming back for seconds was unheard of in my limited experience.

Elton arranged himself on the far side of the table, arraying his books as a shield for the notes and maps we weren’t to see. He set out his dice, hands thick-knuckled from years of karate punches. The game master has to be the main creative force, something of an actor to portray those who populate his world, and an authoritative judge to settle player squabbles and end objections.

John sat to my right, annoyingly blonde and chiselled. Money, charm, and looks. Two out of three might be forgivable, but the whole set is bound to breed a little resentment. He ignored the character sheet before him and sat smiling at Mia. She ignored him, poring over her character sheet instead. She seemed to have rewritten the character Elton gave her the last time.

Simon’s mum breezed in with a tray of orange juice and biscuits, followed by Baggage. She opened the window a crack.

‘Mum!’ Simon frowned at her. ‘It’s arctic out there.’

‘A little fresh air is good for you.’ She walked to the door. ‘And I’m thinking of Mia. After a few hours with four boys in it, this room’s a health hazard. Light a match and . . . boom!’ She mimed the explosion with her hands, grinned, and walked off, the cat trailing in her wake.

‘You feeling better?’ Mia looked my way, but I still took a moment to understand that she was talking to me.

‘Uh, yeah,’ I lied.

‘Better?’ Simon shot me a dark look as if I’d betrayed him by consorting with the enemy.

‘Nicodemus ate something that disagreed with him.’ John mimed an exaggerated vomit. ‘Or disagreed with something and then ate it.’

‘I’m fine.’ Nicodemus was my character’s name. So perhaps I wasn’t that imaginative after all.

‘You better be.’ Elton scowled over his defensive wall of books. He might be fearless in a fight and ready to punch out any number of Michael Devises, but when it came to illness he was as paranoid as they come.

‘Well, if you start feeling sick, let me know.’ Mia grinned. She pointed to her character sheet. ‘It says here I have a “cure disease” spell. One size fits all, apparently. From little sniffles to leprosy.’

That would be nice. I muttered something about being fine. Mia had been given a cleric to play. Every newbie gets to play a cleric. They’re the holy men, the priests, and they’re stuck with the healing magic, which means they’re always in demand after the battles but rarely during them. Mia had made hers a woman, a priestess of the Man Jesus, close enough to Catholic to make me think she had a grudge against them. Elton had mentioned something about her escaping a church school at some point, pursued by nuns.

It turns out that a shared imaginary crisis is a great icebreaker. By lunchtime, Elton had us running in panic from a collapsing cave system, and Mia and I were bickering like old friends over the relative merits of our survival plans. Even Simon found his voice, urging us to shut up and run!

An hour later, our small group of adventurers was advancing along a narrow forest path as the sun sank in the west.

‘I’ll climb a tree. A tall one. Maybe I can see an edge.’ Simon gathered his dice. He played a thief with considerable acrobatic skills. When he said things like ‘I’ll climb a tree’, imagination had to kick into a higher gear. In real life Simon had trouble climbing stairs.

‘The tallest are smooth elms,’ Elton said. ‘Super hard to climb. Three skill checks. Roll seventeen or under.’

‘So, a sixty-one per cent chance of making the top.’ Simon gathered the dice.

‘Woah!’ Mia looked up. ‘You just worked that out. Just like that?’

‘He’s a human calculator,’ John said. ‘Watch. Six hundred and eight times two hundred and thirty-seven?’

‘A hundred and forty-four thousand and ninety-six,’ Simon said without pausing, and rolled the dice.

‘That’s incredible!’ Mia blinked.

‘Not really. I was more likely to reach the top than fall,’ Simon said.

‘I mean the maths!’

Simon shrugged. ‘Any pocket calculator can do the same.’ He glanced my way. ‘Nick’s the genius. I’m going to read mathematics at Cambridge. Nick knows that stuff already from his dad’s books. I’m just good with numbers. Nick’s off the scale.’

‘Your dad’s a mathematician?’ Mia turned my way.

‘Was. He died.’

Mia pressed her lips together in a moment’s sympathy, then pushed on. ‘If you’re this wonder-boy, how come you’re not at university already?’

‘When they test him, he pretends he can’t do it.’ Simon looked at Elton. ‘So? What do I see from my treetop?’

‘Not a lot, man. It’s getting dark. The sun’s sinking in the treeline and everything’s black and crimson. But it looks as if the forest ends some miles to the north.’ Elton reached over to sketch an edge to the forest on our map.

Back on the forest track we pressed on, taking the northward choice when the trail forked. We tried lighting lanterns.

‘The flame doesn’t want to take.’ Elton rolled some hidden dice. ‘Like the night just eats it.’