‘And do what?’ I said. ‘Movements from what?’

But already Dr Jones was pushing the boat back away from us, and Soldier John was pulling the sail up. On the deck, those two bulky black bags were sitting, ready for the Jellyfish people to fill them.

‘Movements from what?’ I said again.

‘You know what,’ said James. ‘But we haven’t seen anything here for . . . a while. It’s fine.’

Stinky set off at a run up Long Street. Dr Jones quickly followed, but Staring Crone turned, slowly, to face the Jellyfish.

‘Come on,’ said James. ‘Worry about it later, Martha. There’s nothing here now.’

We set off. It was strange, at first, to run on the hard tarmac on the ground, but do you know, because your feet don’t sink into it you can run further and faster than normal, so it’s also easier too? I’d forgotten the smell of land. The air when you breathe is warmer and drier, so it feels full of dust at first. But there are more smells, too; every few metres the air changes so you might get the tang of crisp seaweed in one place, then the warm petrol-y sharpness of the tarmac, then the clean sweetness of leaves. All within seconds! There were trees, and grass, and I wanted to stop and touch them to remind myself what they felt like, but Stinky was urging us on, so I knew it would have to wait.

We veered round the corner. We hadn’t been able to see this road from the Jellyfish, and it arced upwards, towards the cliff, before curving round again behind another row of houses higher up. Through there, up in the gaps between the houses, you could see row upon row upon row of other houses, and buildings and churches and just . . . loads of things. From the Jellyfish, we’d only been able to see the cliffs on either side, and the row of streets between them. The size of the town had been concealed from us and, although I’d known it was bigger than just what we could see, I couldn’t possibly have imagined what was before me now. Some of the buildings were so big . . .well, what were they for? Where did it all end?

‘Come on, Martha,’ called James. ‘Hurry up. You can look later.’

He ran into a house with an open red front door and empty glassless windows. The shredded brown remains of curtains swayed loosely from the window frames, but otherwise there was no movement.

‘Here.’ Stinky came running out of another house, clutching a black plastic bag already bulging with lumps. He put it into the middle of the road. ‘Put your containers in here.’ He ran back into the house next door.

Dr Jones appeared from the grey building opposite, pausing to put some bottles into the bag before running across the street and in through the open windows of another house.