Mechanically, she got on hands and knees and followed. From the look of the tiny room she entered, things were going to get worse before they got better. Hacked from native soil, the space was too low to stand upright in. The far side was higher but partially blocked by a slide of dirt and rock. Nowhere could she see anything that even obliquely promised the wonders she'd heard spoken of in connection with Lechuguilla. Oscar and Holden crouched with their backs to her, their helmet lights pointed toward the floor, where they groveled before some god hidden from the eyes of unbelievers.

Light swung in a dizzying arc and struck her in the face. "Ta da," she heard Holden say.

"Down the rabbit hole," said Iverson.

Vision cleared, and Anna saw the altar at which the men worshipped. Sunk into the floor was a heavy metal manhole cover with a T-shaped handle welded to its center.

"Cover your eyes," Iverson said, but Anna couldn't. She was transfixed. Grasping the handle he pulled the hinged trapdoor open, swinging it on a counterweight. Corrugated metal drainpipe set vertically in the ground was exposed. A ladder welded to one side led down. Wind gusted from below, blowing dirt into Anna's eyes.

"It blows. Hoo-ee, does it blow," Holden said. "By the air coming out of here it's been estimated Lechuguilla might go three hundred miles or more."

"From where?" Anna asked, and was embarrassed when the words came out in a wail.

"Air pressure," Iverson said. "When it gets low outside, the cave exhales; high outside, it inhales. Pressure equalization is all it is. You last, me first?" he said to Holden. The other man nodded, and Anna wondered if they consistently put her in the middle so she couldn't escape. Iverson slid easily into the pipe and pulled the trapdoor closed behind him. The sudden stillness was a boon for Anna's nerves.