How is it different? Everything looks the same. There’s the fire, not even smouldering any more; there’s the drawing on the cave wall still: the car that made Seb laugh when he drew it imagining people discovering it in thousands of years’ time. Outside, the cold wind blows just like the book says, and little clouds of sand puff up and disappear in the breeze. Even the fish-shaped airship is drifting in its usual place.

I feel different: that must be it.

It’s not just that I am nervous – although I am. It’s that this is no longer fun. Mola’s words come back to me: ‘It’s like a video game to you, innit? Bam-bam-bam, now I’m dead, press “replay”, new life.’

I find myself saying aloud, ‘Well, it’s not a game now, Mola.’

‘Good, I’m glad you realise it,’ she replies. I swing round and there she is behind me and I gasp. ‘You took your time, Dream-boy,’ she says, but she doesn’t sound angry, just impatient.

‘I … I … couldn’t sleep. Hang on … this is a dream, right?’

The old lady rolls her dark little eyes like a teenager. ‘What you think? Course it is.’

‘But … but how come you … I mean …? Are you sharing my dream, or am I just dreaming you?’

‘You gonna waste time worrying about this, Dream-boy?’

‘No, but … why? Why are you here?’

‘You might need some help. Actually … Susan thought you might need help. Now tell me this: how much you wanna get your brother back?’

What sort of question is that? ‘More than anything, Mola! Even more than that!’

She narrows her eyes and nods. ‘Hmm. Sounds like a lot. Come on then. We got a run ahead of us.’

She’s off. We have to get up the beach, up the hill and across the great plain to the canyon, then on to Gravy Lake, before we get to the clearing where Seb was captured. Beside me, Mola runs without even panting. She has lifted up her ankle-length sarong, and her pale legs, knobbly and veined like a crumbly blue cheese, match mine stride for stride.

Soon we’re sprinting across the windy plain, with the Gravy Lake in the distance.

‘Mola!’ I pant. ‘All this super-fast running. It … it will use up my dream-control-power thingy.’

‘So? You got a better idea?’ She’s still hardly even out of breath. ‘You took long time to get here. We not got time for walking.’

She runs ahead of me and soon we are approaching the canyon with the green river of mint custard. I’m beginning to tire, even though I’m dream-running but still: this is going okay, I tell myself. I stop at the river’s edge and sink to my knees, my chest heaving. I count the exposed rocks poking above the surface and forming a route over the water: five steps and I’ll be across.