‘I guess, back in Before I feel like people spent a lot of time pretending, and ignoring things. They didn’t believe sea monsters existed even though there were loads of stories about them and loads of sailors said they’d seen them; everybody still pretended they didn’t exist until those people were dragged under the sea and drowned. And in Before people also said there was nothing wrong with the planet even though sea levels were rising, and the climate was changing, and strange weather was happening. All the people in the world ignored the problem and waited for somebody else to fix the planet. But while they were waiting it just got more messed up.

‘So this time, if we want things to be different, I don’t think we should wait for somebody else to sort out really big problems any more, and I don’t think we should pretend those problems don’t exist. I think we should just do it ourselves.’

‘The other Jellyfish people left though, didn’t they?’ said James. ‘Why does it have to be us who sort it out? Couldn’t we at least go and get them back to help us?’ He zipped a sleeping bag up around him, wriggling down into it so that only his face was exposed.

‘Losers,’ said Lana. ‘They’re from Before. They’re the adults who messed up in the first place and they’re running away from it all again.

‘You can stop whining on about it, Martha. I’m happy to kill the stupid Jellyfish just so we can make the world a better place and everything. But I swear to god, if I get even a droplet of slime on my nice clean clothes then I’ll wipe it on your face.’

‘Whose face?’ said James, sitting up again. ‘Martha’s?’

‘All of yours.’ Lana had started to hum under her breath, as though maybe the thought of rubbing Jellyfish mucus on our faces was making her happy. Like Kate, she was still staring out to sea, but she was looking beyond the Jellyfish, at the setting sun and the miles of shimmering water.

‘I am totally in favour of ripping that massive white slime-ball into shreds,’ said James, ‘but by killing it we’re not exactly creating a better world for jellyfish, are we?’

There was a long moment when we all contemplated this deep moral issue. Actually, being honest, it was a brief moment for me. I spent most of the time we were silent thinking about how we were going to kill the Jellyfish, and picturing myself with that long blonde hair and the ninja skills again. I’m pretty sure it was also brief for Lana too, because I mainly saw her squinting at the side pocket of the yellow rucksack, where she’d put a selection of different nail varnishes.

‘I don’t think jellyfish normally eat sheep,’ said Kate.

‘What?’ said Lana.