Echoes in the Dark

The drop swallowed Tarik-oglu feet first.

His heels found purchase on rough lime ridges ten feet below the lip, the impact shooting through his shins to rattle the teeth in his skull. He jammed his elbows hard against the opposite walls of the shaft, wedging himself into the vertical chimney. Granite on his spine, raw dressed ashlar on his breastbone. Beneath his coat, the twine-tied parchment packet pressed firmly against his ribs, protecting the brittle cylinder of bone-ash mortar he had pried from Pillar Twelve.

Above him, the darkness hissed.

The sound was the synchronized, frantic breathing of three men who no longer used their lungs to speak. Boots scraped the flagstones of the inspection pocket over his head, followed by the dull rattle of pebbles raining down the chute. A lantern swung past the upper opening, casting sharp, jagged shadows across the greasy stone. In that split second of yellow light, Tarik saw a hand grip the lip—fingernails worn down to red pulpy nubs, gray dust packed deep under the cuticles, skin peeled back from the knuckles where stone had ground flesh to gristle.

"Keep dropping," Yasar-tay hissed from below, his voice a dry rasp rising through the dark. "The chute stays vertical for twenty paces, then pitches south toward the secondary siphon. Do not drag your heels on the relief seams unless you want your ankles snapped."

Tarik let his elbows slip, sliding five feet down the throat of the rock before locking his knees across the chute. The stone tore through the wool of his trousers, scraping skin from his calves. The air here was heavy with sulfur, wet limestone, and the unmistakable sweet stench of decayed bone meal.

A heavy thump shook the masonry above him. One of the infected sentries had entered the chute, dropping down with unnatural disregard for broken limbs. Tarik heard the wet snap of an ankle hitting a ledge, but there was no grunt of pain—only the rapid, insectile scrape of calloused palms dragging along the stone.

"Yasar-tay," Tarik called softly, his voice deadened by the narrow channel. "How far to the flue floor?"

"Far enough to kill you if you let go," the blind sapper answered from the gloom below. "Flue Four is nineteen minutes from its scouring wash. When Aysun-bek turns the reservoir capstan, twelve thousand gallons of headwater will tear through this duct like an iron ram. If we are still in the siphon when the surge hits, the current will pulp us against the intake grates."

"I am aware of the hydraulic schedule," Tarik muttered, lowering himself another yard by sheer arm strength.

"Good. Then hurry up and fall."

Tarik released his grip and slid. The stone walls narrowed, pinching his shoulders until his coat seams groaned, then widened abruptly into an intermediate relief pocket. He hit the floor rolling, his palms slamming into slick silt and sharp masonry spalls. He immediately reached inside his coat. The oilcloth wrapping was intact; the fragile cylinder of mortar within had not crumbled.

Yasar-tay was already crouched against the western jamb of the chamber, one ear pressed flat to the damp mortar line, his blind eyes white and milky in the gloom. He held his sapper pick across his knees, the steel point dripping with black moisture.

"Two coming down the vertical chimney," Yasar-tay said without turning his head. "One more crawling through the lower ventilation conduit to our left. They smell the fresh fracture on Pillar Twelve. They know the stone is loose."

"They do not smell stone," Tarik said, rising to a crouch and shaking the numbness from his fingers. "They smell the calcined bone in the binder. The marrow."

"Call it whatever you like, Surveyor. They want to swallow it, and they will chew through your ribs to get it." Yasar-tay tapped his pick against the floor slab. The pitch was flat, dead, choked with silt. "The lower siphon branch is blocked. The sluice gate must have jammed during the last inspection cycle. Silt and broken ashlar have dammed the lower bypass two cubits deep."

Tarik stepped to the arched opening at the southern end of the pocket. He pulled his steel tuning rod from his belt, striking it against the heel of his palm before holding the vibrating prongs toward the dark aperture.

The sound that returned was wrong. Instead of the clear, ringing fifth that a true load-bearing vault should cast back, the chamber hummed with a flat, discordant rattle.

"The arch is carrying a double load," Tarik said, feeling along the edge of the lintel with his bare fingertips. The stone was cold and sweating, but the bedding joint was soft. When he pressed his thumb against the mortar, it gave way like damp sand. "The entire upper flue rests on this single relief lintel. If the siphon below is choked, the water pressure will back up into this chamber before it reaches the main sluice."

Above them, boots struck the ledge of the chute.

A body dropped into the vertical neck five yards up, sliding down with terrifying speed. A face appeared in the gloom—Guardsman Temur, a veteran who had stood watch on the south battlement for six campaigns. His mouth hung open, jaw distended, lower teeth caked in gray paste. Whitened flakes of pulverized mortar clung to his beard. His eyes were wide, vacant, staring past Tarik as though looking at a banquet laid across the empty air.

Temur reached out with both arms, his fingers hooked into rigid claws.

Yasar-tay lunged forward, thrusting the butt of his sapper pick straight into the soldier's chest. The blow arrested Temur's descent with a hollow crack of breaking ribs, but the guardsman did not cry out. He simply grabbed the ash shaft with both hands, pulling himself downward along the wood, his jaws snapping in the dark with a dry, rhythmic clatter.

"Tarik!" Yasar-tay snarled, his heels sliding on the greasy silt. "He does not care about the pick! Cut his throat or break his neck!"

"Hold him!" Tarik snapped.

He did not draw a blade. A knife through a man's windpipe would do nothing to stop the two others sliding down behind him, nor would it clear the dammed siphon before the reservoir sluice opened.

Tarik unhooked his horsehair line from his leather pouch. The heavy brass teardrop bob swung from the cord, catching the faint reflection of the lantern light far above. He tied the free end around the central tine of his steel tuning rod, then jammed the rod directly into the soft bedding joint above the relief lintel.

"Surveyor, what in the seven hells are you doing?" Yasar-tay shouted, wrestling the thrashing soldier whose teeth were inches from his collarbone.

"Calculating the shear angle," Tarik said between clenched teeth.

He flicked the brass bob with his middle finger. The heavy teardrop swung in a tight, rapid pendulum against the stone face. Tarik watched the line's deviation. The horsehair did not hang true; it pitched seven degrees inward toward the relief pocket's southern corner, drawn by the hollow cavity behind the masonry veneer.

The original builders had taken the same shortcut here that Evren-oglu had permitted at Pillar Twelve. The outer stones were two-inch dressed ashlar; the core behind them was nothing but loose rubble, bone-ash mortar, and unslaked lime.

"The keystone seat is brittle," Tarik said. His voice was steady, purged of everything except the geometry of mass and failure. "The entire bypass vault is held by this one bearing point. If we shatter the wedge, the relief arch collapses backward into the vertical flue."

"And buries the shaft!" Yasar-tay grunted, slamming Temur's head against the sidewall with a savage twist of his arms. "Along with us!"

"Not us," Tarik said. "The fracture will run along the bedding plane. It will drop thirty tons of ashlar straight down the vertical chute like a portcullis. But you have to hit the tuning rod on the third beat."

"I am blind, you lunatic!"

"You have ears," Tarik said. He grabbed Yasar-tay's forearm, guiding the sapper's calloused grip to the pick head, aligning the steel spike with the protruding shank of the tuning rod. "Listen to the ring. When the vibration drops from high pitch to dead iron, strike with everything you have."

Above them, a second pair of boots hit the chute ledge. Another guardsman dropped down, his fingers clawing at the mortar seams, his jaw working in frantic, silent hunger.