Around the other side of the pool, several ledges created narrow terraces up the rock wall. Although it wasn’t obvious to the naked eye, not unless you knew what you were looking at, these ledges created a perilous stairway into a cave hidden behind the waterfall. They ducked through the falling water and stumbled on damp rock made slippery by algae. Xilsi flailed, and Jirvy caught her before she fell, but she shoved him off and stumped after Elen, up into the back of the cave and onto drier ground, where not enough light reached for algae to grow.

The large cave bore no signs of recent habitation. Instead, in the very back, rose square pillars surrounding a six-sided beehive-like structure. They weren’t ruins, precisely, but so old they seemed instead like the bones of a long-dead creature. Luviara flitted around them like a moth to flames.

“Look here!” she cried. “This is no beehive. The structure surrounds a shaft. Perhaps it is a well? Can it be climbed down? No, never mind. I think it’s blocked by fallen stones.”

“Wow! Have you ever seen such a thing?” said Kem to Ipis as they surveyed the musty depths.

“Did swalters really delve this? I thought they were more like unusually intelligent animals, not builders like us.” Ipis traced the curve of a rusted iron wheel. “This looks like it could have been part of a well winch.”

Simo said, “Ipis, don’t touch anything.”

Elen got out her lantern and tinder box, and lit a wick. By the flickering light, she led them into the darkest recess of the cave, which led into a tunnel just wide enough and tall enough to fit Fulmo’s body, as long as he hunched his shoulders to keep his head down and tucked his arms against his chest. As they ascended along a curving tunnel hewn through the rock, spiraling upward, he had at intervals to turn sideways to squeeze through.

Luviara crowded up behind Elen to get the best use of the light. She was beside herself with excitement. They came to a handsomely carved archway of floral vines and gamboling lynx cubs. Without warning, Luviara turned aside and entered.

“Interlocutor, I pray you, stop,” said Elen.

Luviara paid her no attention as she strode toward a farther intersection barely visible at the edge of the lantern’s aura. She called back, “But this is astonishing. An entire warren of rooms and more rooms and yet more rooms, a village carved inside the cliff!”

Jirvy shoved past Elen. “Interlocutor! Halt! There’s a trap right ahead of you. A thread across the tunnel. Take a step back!”

For a tense moment, Elen feared Luviara would stubbornly keep walking, but then the theurgist took a slow step back.

“Keep moving,” said Jirvy.