Chets laughs. ‘I knew you were a failure at maths, but I thought at least that you could count to six, which is how many there are of you, not that it will make a difference.’

‘Oh, I wasn’t counting Trent,’ I say. ‘I mean, let’s face it, he’s not going to help.’

‘I seem to remember that I took out Chets at Crater Lake when he was chasing, and almost catching you,’ Trent says.

‘That was an accident,’ I say. ‘You were trying to save yourself.’

‘And you wouldn’t know your loser friend was a wall-crawler if it wasn’t for me.’

‘Also an accident,’ Kat says.

‘My point is that he can’t stop all of us if we try to leave,’ I say. ‘Can you, Chets?’

He laughs in a very un-Chets-like way. ‘You have no idea what we’re capable of.’

And I don’t. Which is why I’m trying to find out. ‘Seen it all before, mate,’ I say.

‘But you haven’t. You have only seen our first 229 incarnation. Now we are stronger in every way, and resolved to our purpose. At all costs.’ He opens his mouth, stretching it wider and impossibly wider, his lips peeling back until there’s a gaping black hole where his mouth was.

‘I’d forgotten how gross this is,’ Kat says, all of us staring transfixed by the horror.

‘Is he eating his own head?’ Karim whispers.

From the dark inside Chet’s mouth, I see movement. Something is twitching around in there. Then shiny black structures, like thick insect legs, emerge from Chets’ mouth – one on each side. They grow to about twenty, maybe twenty-five centimetres long, and the hooked ends clack together like pincers.

‘Mandibles,’ Ade says. ‘They look different from last time.’

‘They’re thicker and hookier,’ says Kat.

‘Sharper edged, too. Look like they could take your arm off.’ Mak edges a tiny bit closer to get a better look, and Chets snaps the mandibles at him in a way that suggests he’d happily give the arm chopping a go. Then he makes the noise – the noise that we refer to as ‘The Hoche’.

‘Take cover!’ Mak yells, jumping over the coffee 230 table and flipping it onto its side in one smooth motion. It crosses my mind that I should probably work out more, cos he and Chets are totally shaming me, but then I move, pushing Kat and Karim towards the coffee table. ‘Ade, the chair!’ Mak shouts. She’s the furthest away from the table, and as Chets’ pincers spread wide and a ball of yellow slimy stuff shoots out from in between them, I can see she won’t reach the shelter of the table. She freezes for half a second, then overturns the chair she was sitting on and dives behind it just in time.