Charlotte unfastened Jess’ backpack, then lifted her into the tunnel entrance and Madeleine’s arms. The floor shifted and cracked, and there was a trickle of dust. “Move,” said Ellie. “Now.”

First Charlotte, then Ellie climbed up into the tunnel. Ellie looked back towards Jess’ backpack, the only thing they’d left behind. Losing it meant one less weapon against the creatures, but even if going back hadn’t been suicidal, none of them could have carried two of the things. Ellie turned away, but something seized her ankle and pulled.

She screamed and kicked out. One of the creatures – one of the creatures was awake, and attacking her. But as she rolled onto her back, Ellie saw that it was Liz Harper, one side of her face a black and red ruin, a gaping socket for an eye, snarling through gritted teeth as she tried to drag Ellie out of the tunnel and herself in. Ellie kicked at the scorched face, but Liz’s grip refused to break, and the sound of dust trickling was joined by the clatter of bones as the bone floor sagged in the middle, then gave way, Jess’ pack tumbled into the hole and vanished into blackness. In the same moment, Liz’s full weight fell on Ellie’s leg, and she was being dragged back out of the tunnel.

Charlotte lunged past Ellie, driving the butt of her shotgun into the crown of Liz’s head, into the ruined face, till Ellie heard things crack. Liz’s grip slackened, and gravity did the rest. Liz clawed and scrabbled for a handhold, but it was too late, especially when Ellie kicked out wildly with both legs. Liz Harper fell backwards into space and was gone, leaving only a scream that might have been terror or rage.

About half the blockage remained in place, anchored by the dried, packed earth. Then it, too, cracked and fell away. A few chunks of bone and earth clung to the shaft’s edges, but otherwise there was only blackness. When Ellie shone her torch down the shaft, she saw only a long stone throat seemingly without an end.

“Jesus Christ,” muttered Charlotte.

“Got to go,” said Madeleine. “Haven’t much time left.”

She was already moving down the tunnel, shining her torch ahead. The walls were lined with those now-familiar web-shrouded alcoves, occupied like the others they’d passed. The creatures they’d fought so far could only be a fraction of the army asleep down here. And these were just the advance troops, the attack dogs. The real enemy, the big guns – those were sleeping down here too, waiting to be woken up.

Charlotte looked at Jess, then Madeleine. “Go on,” said Ellie. “I’ll look after her.”