The cold water that trickled down the upright seam of Entry hall 451 tasted of crushed white chalk-stone and very old iron. It ran in a thin, nonstop ribbon between two blocks of dressed dark rock, cutting a greasy green furrow through the stone crust before dropping eighty arm-lengths into the drainage trough beside Qiao Ming’s bare heel.
He didn’t draw back his foot. The soles of his feet had long since hardened against the chill of the floor flags, their skin thick as boiled hide, yellowed at the calluses and scored with small, white crescent scars left by stone-hard tube-worms and shards of dead shale. To sound an unfamiliar vault, a land-mapper needed direct contact with the stone. Leather muffled the tremors of the keel. Iron boots turned the subtle groan of the foundation arches into meaningless clatter. Only bare flesh, pressed flat against the pale limestone, could register the micro-ground-shaking shudder of forty leagues of overhead salt water bearing down upon the ceiling vaults.
Beside him, the oil lantern sat upon an overturned land-mapper’s crate. Its wick, braided from dried sea-moss and soaked in rendered seal animal fat, cast a steady, smoky yellow circle across the threshold. Within that circle, Yan Zhiqiu knelt with her knees tucked into the hem of her salt-stiffened cloak. The Broken Slate of Yan-Luo rested across her thighs, its hardened northern edge tilted toward the flame. Her fingers, stained to the second knuckle with carbon ink and iron gall, traced the tiny carved…
