They were walking down a long corridor that seemed to run the length of the building, with other corridors off to the sides and windows into open-plan offices. There were glossy framed photographs on the walls, of brightly coloured pills, and smiling, happy, healthy families, nurses and doctors in impossibly clean hospital wards. Smiling. Attractive scientists peering into microscopes. Smiling, smiling, smiling. There were also some slightly random photos of nice landscapes and sunsets. It was clear what message they’d been trying to put across – everything is all right in the world, we will look after you. You’re safe in our hands.

Yeah. Right. Good one.

When it had come down to it the doctors and scientists had been taken just as much by surprise as everyone else. They’d been no help at all. They’d been struck down by the disease along with all the rest of the adults. Died before they could find a cure, or even find out what the disease was, where it had come from.

It had all happened so fast. One day it was all sunsets and smiles, the next …

Night of the living sickos.

At the end of the corridor was a lobby, with lifts on either side and thick glass doors at the back. A sign above the doors read UNIT B. ENTRY TO AUTHORIZED PERSONNEL ONLY. To the right of the door was a flat electronic card reader and a small numeric keypad.

Blue shone his torch at the flat black panel of the card reader.

‘Now what?’ Emily asked.

‘Simple,’ said Einstein. ‘We press our access card to the pad then punch in the secret code and – ta-dah – the door will magically swing open.’

Blue gave Einstein a look that said he was just holding back from punching his teeth out. Achilleus went to the doors and studied them up close by the light of Paddy’s torch beam.

Jackson had a thought and pushed past him, gave the doors a gentle nudge. They swung open.

‘You guys never learn, do you?’ she said, walking through.

On the other side of the doors was a stairway that split in two and went down either side of a square central column. There was less decoration in this area. Nobody had bothered to stick up any inspiring pictures. Jackson sniffed the air. Often when you went into a building that had been empty for a long while the air was stale and nasty. Here it didn’t smell of anything. It was as if the sterile, air-conditioned atmosphere the building must have had in the old days was somehow still lingering.

Blue pushed to the front and led them down the stairs, going noticeably more slowly now. At the bottom was another corridor leading straight ahead into darkness.

‘It’s gonna be a pain getting the supplies back up them stairs,’ said Blue, looking back.