I walk up to the nearest person. From what I can see of her figure she is only a girl, maybe thirteen, with a cloud of dark hair behind her mask. She’s sitting on the ground in PJs covered with emojis that spring out at me in AR. I kneel beside her.

‘You can take off this mask,’ I tell her. ‘You can open your eyes and look around. There’s a whole other world here. A world that’s alive and awake, that will talk back to you. Do you want to see it?’

Her mask turns up towards me. Her eyelessness is spooky. She reaches up and tries to take the mask off, but it seems to be stuck to her.

‘How do you get it off?’

Her voice is muffled.

‘Let me try.’

I reach out and lift the mask off easily. I can see her face in the neon light of the platform: smooth, young, half-smiling as she opens her eyes. Her emoji-PJs begin to acquire some colour as she becomes conscious.

‘Who are you?’ she says, taking in the sight of me bending over her, dripping wet.

‘I’m Charlie Aaron, and I’m a dreamhacker.’

I reach out to shake her hand and a fish falls out of my cleavage. The girl leaps to her feet, startled.

‘You don’t need this mask,’ I tell her, and I change the mask into an old-fashioned silver key. Then I draw a rectangle on the grey Sweet Dreams platform, with a keyhole in it. ‘Open the trapdoor,’ I tell her.

She fits the key into the lock and the trapdoor opens to reveal a staircase winding down into the luminous wilderness of the Dream City.

‘It’s yours to explore and change,’ I tell her. ‘You can do anything you want with it. And if you meet any monsters, remember they belong to you.’

I pluck the key out of the lock and give it to the girl.

‘What am I supposed to do with this?’ she says.

‘Whatever you want. Sew it into your sports bra, I don’t care. Just don’t give it to anyone else, and don’t bloody lose it. Now, off you go!’

She looks down through the trapdoor, into the brilliance and complexity of the Dream City, her emojipj’s bursting into laughter icons and giggling sounds. Then, barefoot and wide-eyed, she starts to descend.

Meera is at my side.

‘I’m scared for her,’ she whispers. ‘That place down there is a complete unknown, anything could happen.’

‘I’m scared for all of us,’ I say. ‘But being unconscious isn’t going to save anybody from anything. We’ve all got to wake up.’

So I leave the girl to her adventures. I run through the greyscale crowd tearing people’s masks off and shouting, ‘Wake up! Wake up!’