‘Here, let me see,’ Elspeth said, lying on her stomach and reaching into the void, rummaging around through the remnants of the insulation where Meggy’s foot had gone down. When she pulled her hand back out, it held a tiny, round white ball.

A crack ran through the skull, and a section had come away, but the features were still clear.

‘It’s a baby,’ Meggy said.

‘It was a baby,’ Elspeth corrected.

Xavier put his hand over the sphere of bone and took it gently away, putting it delicately on the floor.

‘Now it’s one more reason for us to get out of here as quickly as possible,’ he said. He put one arm around Elspeth and the other around Meggy. ‘We can do this. But only if we don’t get distracted by our fear. When we get out, we’ll make sure everyone who died here is taken away and buried. We won’t let them be forgotten. I promise. I need you to be brave. Nothing’s changed. Meggy, ready to try again?’

‘I guess,’ she said. ‘Not with my right foot, though. I really hurt my ankle.’

‘Left foot this time,’ he said. ‘Clear more of the insulation before you try again. We can’t have any more injuries.’

They returned to their original positions.

Meggy made a space so she could see before she stamped again. She brought her foot up and smashed it downwards. No impact. They peered into the hole. The plasterboard hadn’t even registered the blow. Again, Meggy raised her leg and slammed her heel into the board. There was an echo that seemed to hit the ceiling above them and come back down towards their heads, but no result.

‘We’ve got to keep trying,’ Xavier said. ‘If he was in, he’d have heard that by now. Give it a few more goes, then Elspeth will have to take over. I know it’ll be harder to get your feet in, but we’re out of options.’

‘How do you think he killed those other people?’ Meggy asked.

‘I have no intention of finding out,’ Xavier said, gripping her chin and making her look straight into his eyes. ‘Because it’s not going to happen to any of us.’

‘I have an idea,’ Elspeth said. ‘Meggy can’t harness enough force to damage the plasterboard. But if I stood on it long enough, put all my weight through a single small area, then sooner or later it would weaken, right?’

‘The rafters are pretty close together. Meggy can’t hold you, I’m not mobile enough to guarantee I can stop you from falling, and you might get yourself injured either by the rafters or if you fall too far, too fast. There’s your left hand to think of, too.’

‘You can’t do that. It’s dangerous.’ Meggy shook her head. ‘I won’t let you.’