Chapter 22: The Secondary Cavern

The chalk marks had started running together in Gordon's head at the forty-third circle, which was when he'd begun counting them instead of the feet between them, which was a mistake and he knew it was a mistake even as he was making it because counting provided the illusion of measurement without the substance of it, and the substance was what mattered down here. He switched back to feet. Fifteen feet per mark. Forty-three marks. Six hundred and forty-five feet from the entrance, give or take, which meant the entrance's pale comma of light had been swallowed by the dark approximately five hundred feet ago and they were now, by any reasonable definition, inside something that did not care about their presence.

The passage had changed three times since they'd passed the last industrial infrastructure — the rusted tracks, the collapsed timber shoring, the drip-stained concrete of the mine's operational history. First it had narrowed, and they'd moved single-file through limestone that pressed close enough that Gordon could feel the cold radiating off it through his shirt. Then it had dropped, a rough slope of fifteen degrees that sent loose shale skittering down ahead of them in small ricochets of sound that went on longer than they should have. Then it had widened again into something that wasn't a mine shaft at all.

Gordon stopped.