Tentatively, he peered more closely at the stone beneath his feet. He licked his fingertips, then hovered them a centimetre or so above the crack. Immediately his fingers felt cold. There was: there was a definite draught. Meaning … what exactly? The stones in this corner of the clearing weren’t the same as the markers on the graves. If anything, they looked more like the slabs on the floor inside the chapel.

Ben stood up straight. He took in the position of the graveyard in the clearing, and the chapel fifty metres or so further up the hill. The space between was filled with trees. But not trees like the ones elsewhere in the woods: the gnarled chestnuts and impossibly tall oaks. The trees between the graveyard and the chapel were younger, and Ben already knew the reason why. He’d studied enough pictures of Beaconsfield through the ages to know that the younger trees had been planted on the site of the original chapel. That was why the graveyard was here in the first place, and it was partly because of the graveyard that the chapel had been moved. Whoever had rebuilt the school had wanted the new chapel to be bigger, better, and the only option short of exhuming all the bodies in the cemetery was to position the new building further up the hill.

All of which meant that the stones beneath Ben’s feet had probably come from the original building. And if there was a cavity somewhere below them, that meant …

With something between trepidation and excitement, Ben dropped on to his hands and knees, and tried to peer through the crack. He worked his fingertips into the gap, the way he had before, and this time pulled with all his strength. But it was no use. The slab didn’t shift.

Frowning, Ben stood upright again, and surveyed the cluster of stones at his feet. The slab was maybe half a metre wide and twice as long, and one end seemed to disappear into the slope. After stealing another glance around the clearing, he took a step forward, positioning one of his feet on the grass, and the other on the slab beside the crack. He raised his knee, then stamped down with his heel. He stamped again, and again, and again – and all at once there was a sound like a gunshot echoing through the trees.

Ben stumbled backwards on to the grass, almost falling, so startled was he by the noise. He fully expected to see one of the teachers, or even the headmaster himself – the noise he’d heard somehow the sound of their fury. But there was no one, and when Ben looked back at the slab, he realised the rifle sound had come from the slab splitting further in two.