Sam was up. He looked at his bike. The front wheel was bent out of shape and the tire had burst. All that work. Wasted. He would have to walk now. He might never be able to catch up with the others.

Actually, he would have to run. There were more grown-ups closing in on him.

He stumbled forward and felt his legs wobble. He was dizzy from the fall, and limping. He forced himself to move, though, watching his dirty sneakers as they slapped down on the road in front of him. He needed somewhere to hide. He passed some steps going down to a public toilet. No. He didn’t want to get trapped. He remembered the tube station. Maybe if he could get in there, in the dark, he’d be all right. Just so long as he got safely off the streets. He broke into a run and dodged past some railings. Two fathers came lolloping up behind him and smashed into the ironwork.

A car had driven into the side of the tube station, creating a gaping hole in the big steel shutters. A skeleton sat at the wheel. You normally never saw skeletons anywhere.

Sam ducked in and clambered over the ticket gates. He fumbled in his pocket for the flashlight he’d picked up at Waitrose. Pumped the handle and flicked the switch. He scribbled the blue-white beam over the walls. There was only one thing for it: he would have to go down toward the platforms. A shriek outside spurred him on, and in a few seconds he was rushing down the unmoving escalator two steps at a time, his flashlight beam zigzagging wildly, showing flashes of torn posters for vacations and televisions and shops and other useless things.

It was a mess at the bottom. Fallen bricks, tangles of wires, pools of yellow water—a dead body crawling with maggots. There had been a fire here recently, and he could smell smoke.

The grown-ups were still following him. They were on the escalator, their noisy progress echoing off the tiled walls.

Grunts and heavy breathing and clumsy feet. Sam looked quickly to right and left, and chose right.

He ran on through the passenger tunnels until he reached a platform. He quickly shone his beam along the rusting tracks. There was water and trash lying between the rails. He jumped down, pressed himself against the wall below the platform, and switched off his flashlight.

It was utterly dark. A darkness like he had never known before the disaster. There was no source of light anywhere. No winking safety bulbs. No glow of electricity. The world had ceased to exist. Sam suddenly became aware of his other senses. First the cuts and scrapes on his bruised body, then a metal bolt digging into his side. Next came the smells of dust and oil and damp and decay pressing into his nose. Then his hearing. Nearby some dripping water, and a small animal moving about, a mouse or rat. Farther away, but moving closer, the grown-ups. He could sense that they were unsure in the dark. Their footsteps uneven. There was a cough, a sneeze, chattering teeth. Long fingernails scraping on the tiles as they felt their way along.