Liz climbed down into the barrow, to the rope hanging from its piton, peered down and listened. She nodded to herself, and slung her shotgun across her back.

Madeleine limped towards the rightmost entrance. “This way.”

“How d’you know?” whispered Charlotte.

“Cobwebs.”

“Huh?”

Madeleine pointed. “There’s still a load of ’em hanging down over that entrance. Other ones’ve been swept clear.”

Ellie saw she was right. Ragged scraps of webbing clung to the edges of the other entrances; over the third, a thick curtain still hung down to the floor.

“And…?” said Charlotte.

“The tunnel’s not in use,” said Ellie. “Which is good, as we don’t want to run into any more company than we have to. Long as the thing actually goes somewhere.”

“It does,” said Madeleine. “It will.” She moved to the entrance, stooped with a pained grunt, lifted the webbing – which Ellie saw, her stomach rolling queasily, was several inches thick – and disappeared under it.

“Great,” muttered Ellie, then picked up the sputtering road flare and followed. The web was filled with desiccated insects, and then with scuttling movement as tiny white spiders raced away from the intruders on spindly legs like long pale hairs. For a moment Ellie thought she was seeing tiny, embryonic versions of the monsters. She shook her head, dipped under the curtain and went into the darkness, holding the flare.

She almost cried out at what it showed her. The tunnel was perfectly round, with ribbed walls, as if a huge earthworm had slid and burrowed through the rock as its small, common cousins did through soil. Neither that nor the row of arched niches cut into the walls on either side every two feet had almost shocked a cry from her: that had been caused by the thin white things folded up inside every niche, each shrouded in a pallid cloak and with a hood hanging down over its face.

They didn’t move or even breathe that Ellie could see, but showed no sign of either mummification or decay. Other than their additional shrouds of cobweb, it was all too easy to imagine them stirring into sudden life.

“Budge up,” whispered Jess, bumping into Ellie from behind, then added “Fucking hell.”

“Yeah.” Ellie hadn’t moved since seeing the creatures; Madeleine had gone forward, almost out of sight. She went after her friend, Jess behind her.

“Lights out!” Charlotte whispered, behind Jess. “They’re coming.”