Blue had got them up at sunrise. The warehouse kids had made them some beds down among the shelves, piling up mattresses and sleeping-bags and duvets. They’d kept close to each other for security. It had been dry and quiet and warm, but few of them had slept well.

They’d negotiated with the Twisted Kids about what they could take. It hadn’t taken long. The girl they called the Warehouse Queen had been in charge, but she never seemed to speak, just sat there, slumped in her wheelchair throne. The other kids hovered round her and seemed to know what she was thinking without her having to say anything.

The deal they’d struck was that Einstein would be allowed to take whatever they could carry as long as they also took some of the Twisted Kids back to the museum with them. They were supposed to find out what was going on in the outside world. Check that it was safe at the museum, and then, when the time was right, report back to the warehouse so the Queen could decide on their next move.

The Twisted Kids were being cautious. Patient. They’d had fifteen years to think about it, after all.

Ollie slotted the steel shot into the leather pocket on his sling. Stretched the elastic cords back then relaxed them. Testing it. It was a nervous habit. As if somehow it could have stopped working or got broken since the last time he’d used it.

‘I’ll go and take a closer look,’ he said.

‘I’ll come with you,’ said Ebenezer and Ollie gave him a smile of thanks.

‘Me too,’ said Jackson, moving up from the group of kids who were hiding behind Blue.

‘Yeah, all right,’ said Blue. ‘That’s plenty. Everyone else watch their backs. And watch our backs. Until we know what’s going on, this is a hot zone.’ He turned to Einstein, suddenly angry. ‘Why would they open the doors?’ he hissed accusingly. ‘Why would they come out? We told them to stay put. They were safe in there.’

‘Don’t ask me,’ said Einstein. ‘I was with you, remember?’

‘They’re your kids. If they’ve done something stupid they’ve put us all in danger.’

Ollie shook his head and moved off. What was the use of arguing about it now? The only thing to do was find out what had happened and get it sorted. He and Ebenezer and Jackson crept through the trees, sticking to the shadows. He was sniffing the air, searching for that distinctive sickly, sweet-and-sour perfume of rotten adult. All he could smell was greenery, earth, a fresh new world freed from the pollution of cars and planes … and people …