The Inverted Floor

The floor realm struck upward like an iron plate.

Sorcha did not try to plant her boots. In the last fifty feet of the drop she had cast her tethered flint chisel ahead into the updraft vent, watching the line snap taut to gauge the exact second her fall would peak. To meet reverse stone with stiff legs was to splinter shinbones to meal. She took the shock across the meat of her left shoulder, rolling through thick cushions of damp cave-moss that reeked of rot and cold water. Her ribs groaned against the boiled-leather straps of her dive harness, the sudden downward weight compressing her lungs until her breath blew out in a ragged gasp. Recovering her spent spear, she snuffed the hissing tip in the sodden mulch, cutting the charred obsidian head from the shaft to keep the precious glass safe.

Beside her, Mhaire crashed into the limestone scree with a wet grunt. The younger diver did not roll cleanly; her leather pack caught on a jagged rib of white rock, twisting her knee sideways before she skidded to a halt against a boulder.

Sorcha was on her feet before the momentum finished dying. Her joints throbbed with a sickening, heavy pulse. Down here, below the five-hundred-foot midpoint, the pull of the stone did not catch the soles from above; it dragged at the blood in her ears, pulling her spine downward toward the endless rock floor. For a diver born on the high ceiling roosts of Ceann-Aghaidh, where stone held you fast to the roof and the void yawned below, the sensation was a sustained blow to the belly. The sky was not open void; the sky was a ceiling of jagged black basalt five hundred feet overhead, hanging heavy and distant like an overturned bowl.

"Up," Sorcha whispered, her hand clamping on Mhaire’s collar. "Clear the impact lane."

Mhaire pushed herself onto one elbow, coughing up a spatter of gray slime. Her right leg trailed limply, the knee swollen beneath the hide wraps. She dragged her spent spear through the mulch, its charred point cold and dead.

"The lowlanders have five hundred miles of level dirt," Mhaire muttered through gritted teeth, "and they choose to bed down in swamp mud."

"Quiet." Sorcha hauled the diver behind a fractured pillar of pale limestone that rose like a broken rib from the floor.

Dropping to one knee, Sorcha ran firm fingers down Mhaire's injured leg, testing the joint. The kneecap was intact, but the ligament was badly strained. She drew her skinning knife, slit the sinew binding from Mhaire's spent spear, and worked the scorched obsidian point free from the charred haft. She stowed both their spent glass heads into the padded pouch of her belt. Obsidian was too scarce in the ceiling roosts to leave behind on the floor.

Thirty paces to the east, across an open apron of white talus, lay what remained of Eachann. The fall from the midpoint without pitch-braking had left little to bury. The smear of crimson dust and shattered bone was already drawing blind cave-beetles from the shale cracks. In the cold draft of the lower floor, the blood steamed faintly against the pale stone.

Sorcha ignored the smear. Grief was a debt the dead could not collect, and dead divers carried no meat back to the ceiling.

She knelt in the crevice of the pillar, slipping her pack from her shoulders. The floor realm smelled entirely different from the dry, sulfur-cracked heights of the roosts. It smelled of wet mold, crushed grubs, and the heavy, sour musk of penned megafauna beasts. The air was thick, heavy with the moisture that bled down the chasm walls and pooled in the low basins. Every breath tasted of stagnant damp and fungal spores, clinging to the back of the throat like wet wool.

From the leather roll at her waist, Sorcha drew three unlit copper tubes of distilled pitch. Each tube was sealed with beeswax and stamped with the spiral mark of the Ceann-Aghaidh elders. If the pitch cracked, leaked, or took damp in this sodden air, they would have no upward brake to cross back over the midpoint when their raid was done. They would be stranded in this heavy pit until their skin rotted off their ribs and their marrow dried to salt.

"Give me your tether," Sorcha said, keeping her voice flat below the whisper of the updraft chimney.

Mhaire unhooked the braided gut-line from her harness, grimacing as the movement pulled across her strained shoulder. "Can you set an ascent anchor in this chalk? It breaks like stale biscuit."

Sorcha did not answer with words. She examined the bedding plane of the limestone face with her fingertips. Lowland stone was soft, sediment laid down by ancient water seepage, useless for striking weapons or knapping blades, but prone to deep horizontal shearing under pressure. She drew her flint chisel, feeling for the cold draft that leaked through the fissures. Where air blew out from the rock, the fracture ran deep into solid root-rock beneath the crumbly crust.

She found a narrow lateral fault two feet above the moss line. Taking a grooved bone wedge from her bandolier, she worked it into the seam, seating the teeth against the internal strata. She tapped the butt with the heel of her hand until the stone gave back a hard, ringing click—the sound of dense root-limestone biting bone. She threaded the gut-line through the wedge's eyelet, knotting it with the double-bight of the dive-crews, then smeared a thumb of tallow over the fissure to seal out the corrosive damp.

She buried the three copper tubes of reserve pitch beneath a flat slab of shale at the base of the pillar, scoring the rock above with three notched cuts. If they had to run for the chasm with lowlander hunters on their heels, the anchor line would hold three hundred pounds of upward jerk when the pitch ignited.

"Three tubes cached," Sorcha said softly. "Enough to lift two divers and fifty pounds of butchered marrow."

"If we reach the pens alive," Mhaire whispered, testing her swollen knee with a wincing intake of breath. "And if their herds haven't starved before us."

"They haven't starved," Sorcha said, pointing toward the low valley beyond the ridge. "Listen."

Faint and muffled through the damp fog, a low, rhythmic thrumming vibrated through the limestone floor. It was the subterranean heartbeat of the nursery pens—hundreds of great tallow-beasts shifting in their stone paddocks, grunting as they churned through beds of cultivated subterranean moss. The ceiling clans had starved for two seasons on dry lichen and beetle meal while the floor realm gorged on fatty marrow and fresh meat behind their fortress pens.

A short, piercing whistle trilled across the limestone ridge above them.

Sorcha froze, her hand remaining flat against the cache slab.

The sound was not the call of a blind cave-fowl. It was high, clean, and shaped by bored marrow-bone—the three-beat muster whistle of a lowland sweep squad.

Mhaire reached for her short-knife, her knuckles whitening on the horn grip. "They heard the drop."

"They saw the spark," Sorcha murmured. "A turquoise flare in pitch-black air carries ten miles across the floor."

Another whistle answered from the northwest, lower and heavier, vibrating through the limestone beneath their boots. Then came the scrape of horn-cleats against shale—rhythmic, heavy, and unhurried. The sound of hunters who knew their ground and feared nothing that fell from above.

Sorcha gripped Mhaire's harness and hauled her deeper into the black throat of the fissure. The narrow seam cut downward into the rock, angling toward the warm, wet draft of the megafauna nursery pens.

Above them, on the limestone shelf, heavy boots crunched into the gravel where Eachann’s blood was still cooling.