“Safe?” said Arran. “How safe?”

“Food. Water. Clean beds. Medicine. No grown-ups. Does that sound safe enough for you?”

“Where is this place?”

The boy grinned, his face all teeth.

“I thought you’d never ask.”

I’ve traveled all the way across London to find you.”

“Bull. How did you know we were even here?”

“I didn’t. That’s the whole point. My job was to find other people, kids like you.”

“What do you mean, your job?”

“I was sent.”

“Yeah?” said Ollie. “By who? God?”

“Why don’t you let me tell you? Eh?”

They were on the roof, crowded into the little courtyard. Blue and his fighters were in a huddle to one side. Once they were sure it was safe, two of them had gone back to Morrisons to fetch a girl called Whitney, who seemed to be second in command to Blue, just as Maxie was to Arran. Whitney was big for her age and sat there hard-faced, waiting to be impressed. Her hair was knotted into tight braids, and she wore an immaculate white tracksuit that must have been the devil to keep clean. Blue’s fighters seemed to be wary of her and quite respectful. It was easy to see why: Whitney had the look of a girl who had never taken any nonsense from anyone.

Achilleus and his fighters were sitting opposite the Morrisons crew, each side trying to outdo the other in toughness.

Arran sat in a big plastic-covered armchair set back from the fire, his face in shadow. He was happy for Ollie to take charge. Ollie was the best speaker and pretty sharp. He’d see through any lies.

Everyone who had taken part in the battle was shattered, so nobody questioned Arran. If he wanted to let someone else do the talking, that was cool. Truth was, though, he was feeling awful. The whole side of his head was hot, and his ear was blocked and throbbing. He ground his teeth together, let his eyelids fall shut, and tried to concentrate.

It didn’t help.

Whenever he closed his eyes he could see the grown-up back at the pool. Those eyes. That intelligent look . . . that sound. Had it been trying to speak?

“Mwuh ...”

And then it lunged at him, teeth bared, and he jerked his eyes open.

Tried to work out what was going on.

The patchwork boy was speaking.

“Sixteen years ago, something happened,” he said to no one in particular. “As far as we know, everybody on the planet got diseased, but it’s taken all this time for the symptoms to show. Sixteen years.”

“Or else something stopped happening,” said Ollie.

“What do you mean?”

“Either something happened sixteen years ago that made everyone ill,” Ollie went on slowly, “or something stopped happening that had been making people ill. So that anyone born after then was all right.”

“I suppose so,” said the patchwork kid.

“It’s not sixteen years.” Everyone looked at Whitney. “I ain’t been counting the days, but it’s been a year—year and a half—since the disease first showed.”