‘You got a problem here, dude. You’re looking at us like we’re the problem. We ain’t the problem. The problem is yours.’

Blue sat there, arms folded, giving Justin the stone face. They’d come to the museum library and were sitting round a big table in the middle of the room. Justin had thought it would be quieter here, but the place was a mess. It had been turned over pretty badly in the attack last night.

‘I don’t see a problem,’ said Justin. ‘We do all right here. We’re almost self-sufficient and very well protected –’

Blue interrupted him with a harsh bark of laughter. ‘Yeah, we noticed. Wake up and smell the zombies, bruv. Maybe you thought that was a party last night. Didn’t look like no party to me, more like a massacre.’

‘That was not normal,’ said Justin, trying to keep his cool.

‘Yeah,’ said Blue. ‘Which is what I’m saying – you got yourself a problem.’

Justin went quiet, struggling to find the right words. Maxie looked around the room. A group of kids wearing what looked like monks’ robes were clearing up. There were books spilled on to the floor everywhere, broken shelves, some pieces of smashed up furniture and splashes of blood on the carpets.

Brooke noticed her looking.

‘It’s usually so peaceful in here.’ Brooke nodded towards a tall boy with a wispy, underdeveloped moustache who appeared to be in charge of the clean-up operation.

‘That’s Chris Marker,’ she explained. ‘Our chief librarian. He was the one who organized the World Book Day celebration.’

‘Looks more like they was celebrating World Wrestling Federation Day,’ said Blue, and Maxie laughed through her nose and exchanged looks with him.

‘Something went wrong last night,’ said Justin quietly, almost to himself. ‘Someone sabotaged us.’

‘Seems that way,’ said Blue. ‘And that’s your problem. Somebody here don’t like you.’

‘As I see it, there are two explanations for what happened,’ said Justin.

‘Go on.’

‘It’s possible that there’s someone here who’s, as you said, like a, you know, a traitor. And they might have unlocked the doors to let the sickos in.’

‘That’s all there is to it,’ said Blue.

‘But nothing like this has ever happened before,’ said Justin. ‘That’s why I think there might be another reason.’

‘What other reason could there be?’

‘Don’t take this the wrong way.’

‘Try me.’

‘That it’s got something to do with you lot.’

‘Us lot?’

‘Yes. That you’ve come here to try to take over. You somehow let the sickos in and then conveniently turned up to save us all and then we –’