The Megafauna Trail

The sulfur mist hung thick in the throat of the center culvert, smelling of rotten yolk and wet lime.

Ruiseart wedged his shoulder into a basalt niche, wedging the spine of his bog-iron knife against a crack in the rock to anchor a woven sinew net. The floor of the culvert dipped twenty feet below the shelf, carved into smooth gutters by centuries of mineral runoff from the nursery pools. Every four or five paces, boiling mud burped in the darkness, throwing gray steam against the ceiling.

Behind him, Calumh worked on his haunches, driving a notched bone peg into the floor with the flat of a river cobble. Having sent the four hunters south with the thorn-hurdles to seal the southern culvert, the veteran tracker had hurried into the center seam to set the pins himself, muting each strike with a wrap of oily fleece.

"Steam will rot these bindings before the next shift," Calumh whispered, his breath whistling through a gap in his front teeth. "And the mud is eating my boot-grease. If we catch one of these ceiling crows, I want his tunic. Diver wool has to be tighter than this lowland sheep-rot."

"Divers do not wear wool," Ruiseart said without looking back. "They wear boiled calfskin lined with goose fat. If you cut it open, you ruin the weather seal."

"Then I'll take the belt," Calumh grumbled. "A man cannot walk forty paces in this rift without his toes soaking through."

Ruiseart pulled the net's trip-cord taut, looping it over a counterweight of heavy river chert. He did not use iron hooks here. Iron clicked when struck against the culvert's basalt ribs, and any ceiling raider worth her salt listened for metal before stepping around a bend. Instead, he strung thin gut lines ankle-high across the narrowest squeeze of the trail, where the limestone walls pinched to the width of a bull's shoulders.

The tracks on the upper shelf had been clear enough. Two divers had made the drop alive, but the one dragging her right leg was slowing the lead runner. They could not turn back to the ascent chimney without fresh pitch to reverse their weight, and they could not bypass the culvert without swimming the boiling drainage trench. They were funneled.

A wet scrape sounded thirty yards up the passage.

Ruiseart froze, pressing his palm flat against the damp basalt wall. The rock transmitted faint vibrations through his skin: a rhythmic, dragging cadence. Two paces, a pause, a scrape. The limping one.

Calumh shrank back into the cleft, drawing a short club carved from petrified birch. He kept his head lowered, the gray wisps of his beard blending with the wet moss.

Through the drifting sulfur vapor, a silhouette took shape.

The diver moved along the eastern wall, keeping low beneath the steam line. She was slight, her shoulders strapped tight with crossed leather webbing. Her right leg was wrapped from ankle to knee in split cane splints, bound with sinew. In her left hand she held a short ash-wood probe, tapping the limestone ahead of her feet to test for loose scree.

She was alone.

Ruiseart watched her advance past the first steam vent. Her head turned constantly, her chin tucked into her chest to keep her nostrils clear of the heavy gas. She carried no lit brand, relying entirely on the faint amber glow of the nursery vents further down the tunnel. At her hip hung a tubular horn case, sealed at both ends with black wax.

Ten paces. Eight.

She paused right at the bottleneck, her ash probe hovering an inch above Ruiseart's trip-line. She smelled the iron knife wedged in the niche—or sensed the change in the draft. Her body went rigid.

She did not turn to run. With sudden, vicious speed, her right hand dropped to her belt, reaching for a spark-striker and a copper tube.

Ruiseart kicked off the rock before her fingers reached the flint.

He struck her chest with his left shoulder, driving her backward into the mud wall. The impact knocked the wind from her lungs in a sharp, ragged gasp. Her hand whipped up, an obsidian blade flashing from her palm toward his throat, but Ruiseart caught her wrist in an iron grip, twisting the joint until bone grated against bone.

The glass knife tumbled into the silt. Calumh dropped from the shelf behind her, throwing a heavy hemp hood over her head and binding her elbows behind her back with a knot of rawhide.

The diver fought like a snared badger, thrashing her splinted leg against Ruiseart's shins, but she made no sound. Not a scream, not a curse. Only the harsh, wet rattle of air fighting through the hood.

"Hold her knees," Ruiseart said, kneeling across her thighs to pin her against the limestone slab. "Watch the teeth."

"Skinny little thing," Calumh muttered, looping a second cord around her ankles and hauling the knot tight. "Ribs like a wicker basket. I told you they were starving up there."

Ruiseart drew his knife and sliced the harness away from her chest in three clean cuts. He stripped the leather pouch from her belt, then sliced away the tubular horn case.

He pulled the hood back just enough to expose her face.

Her skin was pale, grayed by cold and charcoal smudge, with the sharp cheekbones of the high ceiling clans. A dark bruise swelled across her left temple from the landing impact on the upper shelf. Her gray eyes locked onto his, wide and unblinking, showing neither fear nor pleading—only the flat, venomous hatred of a trapped carnivore.

"Where is the other one?" Ruiseart asked.

The girl spat a mouthful of bloody saliva at his cheek. It struck his jaw and ran down his neck.

Ruiseart did not wipe it away. He picked up the obsidian knife from the mud. The blade was four inches of flawless, smoky black glass, knapped with razor-fine serrations along the belly. It was exquisite work, sharp enough to part skin without resistance. He laid the flat of the glass against her throat, right over the pulsing jugular vein.

"Your companion left you as bait," Ruiseart said, keeping his voice low and steady. "She sent you down the center culvert to trip our nets while she took the high rift toward the calving hollows."

The diver's jaw tightened, but she kept her teeth clamped shut.

Calumh was crouched by her stripped pack, using his bone tweezers to pry the wax seal from the horn case. "Ruiseart. Look at this."

Ruiseart glanced over. Calumh had uncorked the horn. Inside lay three sealed glass ampoules, each no longer than a man's thumb, filled with a dense, oily gray powder that settled like lead dust in the cylinder.

"That is not pitch," Calumh said, sniffing the rim with extreme caution. His weathered face lost its usual cynical smirk. "That is crushed blister-lichen from the ceiling vents, mixed with sulfur ash. One pinch of this in the thermal nursery roots will sour the heat-wells for three leagues."

Ruiseart looked from the ampoules back down to the diver's gray eyes.

A raid for meat was an act of hunger. Raiding parties killed a cow, stripped fifty pounds of flank into back-slings, and burned their pitch to drop back into the void before the horns could gather. But you did not carry blister-ash across a thousand feet of vertical fall to steal food.

Blister-ash was an extermination tool. If the thermal roots went cold, every pregnant megafauna cow in the lowland hollows would miscarry in the mud within two days, starving the floor realm of meat and fat before the dry season ended.

"You did not come for the calves," Ruiseart said softly.

The girl stared back at him through the steam, her lips curling into a tight, bloodstained sneer.

"We gave you five years of our stone," she whispered, her voice rough as broken shale. "Now you choke in the dark with us."

Calumh cursed under his breath, carefully re-corking the horn with trembling fingers. "The other diver. She has the rest of the ash."

Ruiseart stood upright, sheathing his dull iron blade and slipping the captured obsidian dagger into his belt. The black glass was cold against his ribs, heavier and deadlier than any weapon forged on the floor realm in ten generations.

Calumh secured the rawhide cord around the basalt peg, his knuckles trembling as he tested the hitch. "If we sound the war-horns, the sweepers might corner her in the outer pens. But she will hear the horns coming."

"If she hears horns, she cracks the ampoules into the first trench she finds," Ruiseart said. His gaze fixed on the western rift, where the sulfur draft rose warm and steady from the breeding pools. "We don't sound the horns. We track her by the draft."

He looked back down at the bound diver. She had closed her eyes, her forehead resting against the cold limestone slab, waiting in silence for the poison to do its work. The sulfur steam curled around them, thick and yellow, drifting toward the nursery heart where hundreds of sleeping beasts lay warm beneath the earth.