It’s the next day. First day of term. I’m in school, in my form room, and Seb is there as well for some reason that I can’t work out.

Next-door’s Fit Billy is standing in front of the class because he’s our teacher, although he keeps talking in a foreign language that sounds like Chinese and everyone is laughing at him as he takes off his shirt and flexes his muscles.

I look round at my classmates: there’s Mason, and Callum, and the two Darcys, and Kobi, and …

Hang on. Kobi? The cave boy from the book. He’s not even real: he looks like a three-dimensional drawing, and …

We’re not in my classroom, we’re in the cave, from the first big picture in the book. The cave walls are orangey-red from a fire in the middle of the classroom floor, and …

Everyone is gathered at the mouth of the cave and pointing. A huge black-and-ginger dog is walking past on the school rugby pitch outside. When I say huge, it’s about the size of an elephant. Is it a dog? Or … or … a mammoth? A prehistoric woolly mammoth, with a long trunk and huge curved tusks, and …

And from somewhere a memory kind of swims into my head. A memory of something I need to do. Did I hear it? Did I read it? I turn to Seb – Why is Seb in my class, again? – and I find myself saying, ‘Hey, Seb. Am … am I dreaming?’

And Seb says, ‘Yes. Of course you are!’ and I grin with slowly dawning relief. I knew it!

That was one of the instructions, wasn’t it? Written down on the sheet that came with the Dreaminator: ask someone if you’re dreaming and they’ll tell you!

Of course, it makes sense now why Fit Billy’s our teacher, and why Kobi the Cave Boy is in my class, and why there’s a mammoth outside the cave mouth. That is if ‘sense’ is the right word for nonsense.

Another thought crosses my mind, only it’s not the mind that is here: it is like another mind that is observing what is going on. It is this mind that tells me to look at the classroom clock, there on the cave wall, and when I do its hands are moving quickly, but spinning backwards. I know then for sure that I am in a dream. A waking dream!

I turn my attention back to the mammoth, which has cocked its leg on a rugby post and is peeing like a burst water pipe. Everyone is laughing.

There is something I want to try: something else that I recall from the instructions. I stand apart from my classmates, and, while they’re looking out of the window, I stand on my tiptoes and tell myself, Float, Malky, float! and I do, just a bit, as though a wire between my shoulder blades is lifting me up slowly. I start to laugh, even though, as I get higher, it’s a bit scary: if I fall suddenly, I’ll crash into my desk and chair and it’ll hurt.

Did I just do that? Am I floating?

The feeling makes me breathless with excitement. My mind is overflowing with thoughts. Did I really just control something in my dream? Am I really dreaming?

It doesn’t feel like it at all. It feels real – only I can float if I want to.

‘Oh, I say! Look at Malcolm Bell!’ goes a posh voice. I look down and it’s the girl in the blue jumper with the black hair from over the wall. She’s pointing and smiling her lips-together smile and everyone else is going, ‘Whoa!’ and, ‘Awesome!’ and, ‘Check out Malky Bell!’

By the time my head touches the rocky cave roof, I’m getting a bit freaked out, and so I say, ‘Down!’ but nothing happens. I push with my hand against the ceiling, and descend a bit, but then I bob up again, as though I’m a helium-filled balloon.

Seb grabs my shoe and pulls me down, but, as soon as he releases me, I float up again. This time I bang my head hard on the cave roof.

I don’t like this. ‘Down!’ I say again. ‘Let me down!’

This time, though, I really mean it. I am calm. I expect it to happen. And so it does. I flap my arms gently by my sides as I float back to stand on top of the school desk, and I do a little tap dance to make my classmates laugh. Mr Springham, the deputy head, has appeared and even he’s smiling.

Then there’s a scream (probably the Darcys), and people scuttle away from the desk, pointing underneath it. I watch from my position on top of the desk as the knobbled grey-green snout of a huge crocodile emerges, followed by the head and finally the whole fat body.

I look around: everyone has disappeared. It’s just me and a crocodile I have not seen in years.

‘You!’ I say, and it curls its scaly lip in response.

I swallow hard, wondering if it will still work. I hold out my hand towards the croc and, trying to stop my voice from quavering, I say, ‘Cu-Cuthbert.’

Just then, the school bell rings, making a noise exactly like the alarm on my phone, and keeps ringing and ringing and ringing.

Cuthbert begins to shrink, and still the bell is ringing …

It’s working!

He’s getting smaller and smaller.

I feel a surge of elation, power and confidence …