They went off fast. The effects of the disease seemed to accelerate after death. Once they were out in the sunlight they’d probably bubble and split and pop. The Holloway kids called exploding corpses ‘bursters’.

The passageway at the end of the blue zone opened out into a modern extension with a glass wall rising up five floors and supported by a grid of polished grey steel. That would have drawn all of Achilleus’ attention if it hadn’t been for the giant white concrete egg that stood next to the window, filling the space.

‘What the bloody hell is that?’ Achilleus asked.

‘It’s called the Cocoon,’ said Brooke, who had stopped to let the boys catch up. ‘We’ll go up through it to get to the laboratories.’

‘You really got laboratories here?’

‘We got everything, soldier.’

As they made their way up the sloping ramps inside the Cocoon, Brooke explained how Justin had got a couple of the museum labs running under the supervision of a boy called Einstein. It was their hope to discover more about the disease that had so changed their world, maybe even find a cure.

Achilleus said nothing. He found the idea that a bunch of kids might cure anything ridiculous. But if they wanted to arse about playing doctors and nurses he wasn’t going to stop them. That was their business. All he cared about right now was killing the pain in his head.

Paddy, on the other hand, seemed excited and delighted by everything, firing off a stream of questions at Brooke which she answered patiently.

The entrance to the labs was near the top and they emerged from the Cocoon to find several kids hard at work, studying books, squinting into microscopes, fiddling with dirty-looking liquid in test tubes. Some of the kids were even wearing white coats. Achilleus felt sick. He was right back at school.

He set his face into default mode, a lazy mocking grin that said, ‘I am not impressed by you, and I never will be. You will never reach my level. So leave me alone, loser.’

Paddy was off and running, though, pestering the kids, asking them what they were doing, trying to look into their microscopes. Brooke left him with Maeve and took Achilleus through to a smaller room where a giant of a boy who looked about eighteen but couldn’t be was being tended to. A fair-haired guy and a girl with a headscarf were dabbing a nasty-looking wound on his arm with some kind of white cream.

Achilleus raised his chin in greeting.

‘This Holby City then, is it?’

‘Something like that,’ said the girl, and then she switched her attention to Brooke. ‘We thought you might show up here this morning. How bad is that wound?’

‘They looked after me pretty well at the palace,’ said Brooke.