Blue looked at Einstein. ‘I guess you need to come with us. Who else?’

‘Only really Emily.’

‘Who’s Emily?’

‘I am.’ A blonde girl who looked to be about fourteen stepped forward. ‘I’m Einstein’s assistant. Emily Winter.’

‘Emily can help me choose what we need to pick up,’ said Einstein.

‘Anyone else?’

‘Jackson, I suppose, if we’re taking the best fighters.’

‘Good. It’s decided then.’

A small voice piped up. ‘What about me?’

It was Lettis. She went up to Blue, carrying her big book. Ollie smiled. She was a plucky kid.

‘I’ll need to be there,’ she said.

‘No way, babe,’ said Blue, and he shook his head.

‘But I have to come with you. I have to write about it. I have to be there and witness it with my own eyes.’ Lettis was red-faced, almost crying.

‘Who says?’ Blue asked.

‘Chris Marker. The librarian. He told me I have to bear witness to events.’

‘You’ve witnessed enough,’ said Ollie, walking over to her. ‘We’ll tell you all about it later on.’ He put a hand on her shoulder and gave it a squeeze. ‘As Blue says, we won’t be long. We’ll probably be back by lunchtime.’

‘But finding the stuff, the drugs and chemicals and things, that’s the most important part of the story,’ said Lettis. ‘I can’t miss that.’

‘I’ll write everything down, OK?’ said Ollie. ‘I know how important it is to you.’

‘No …’

‘Uh-uh.’

Ollie cut her off. Squatted down to her level and looked into her face.

‘It’s too dangerous, Lettis. We don’t want any more of you to get hurt. Don’t argue. OK? You do what I say.’

‘OK.’

‘Good girl. Now I want you to promise me something, Lettis.’

‘What?’

‘That when we go you don’t open these doors. OK? Not for anything. Nobody goes outside. You understand?’

‘All right.’

‘You only open them for us. When we get back. Will you promise me that?’

‘I promise.’

Twenty minutes later a smaller war party left the church: Ollie with his missile team, Big Mick and Blue and the rest of the Morrisons crew, as well as Achilleus and Paddy. Of the museum kids only Einstein, Emily and Jackson were coming along on this leg. They’d left behind nine kids.

Ollie felt much happier with this set-up. They could go faster and he wouldn’t have to worry about protecting anyone else – except maybe Einstein and Emily. That was manageable. He fell in beside Jackson, who was loping along, her spear over her shoulder.

‘Can you make it your job to look after those two,’ he said, nodding at the ‘scientists’.

‘If you like,’ said Jackson.

‘Any fighting and I don’t want to be worrying about them.’

‘No problem. Emily can look after herself pretty well. Einstein – who knows?’

She smiled at Ollie, which softened her severe-looking face a little.