The Devil's Throat

"Look at the surveyor's notes for the canyon," Penn said, ignoring the suggestion. He pointed his brass rule at a dense cluster of topographical curves marked on the survey map. "Here. Devil's Throat. The canyon narrows to eighteen paces at the midpoint. But look at the baseline readings."

Garth leaned over Penn's shoulder, squinting at the tiny numbers. "The frequency numbers are crossed out."

"Not crossed out. Canceled," Penn said, a sharp note of satisfaction cutting through his flat tone. "The highway’s builders cut the road through a vein of porous serpentinite. Serpentinite absorbs and scatters acoustic vibration. To keep the road from failing in the canyon, the original engineers had to double the depth of the buried bone chambers, but they couldn't balance the harmonic return against the sheer cliffs."

Penn traced the narrow gorge with his chalk. "There is a four-hundred-yard dead zone right at the throat. The road’s warding resonance doesn't resonate into the canyon walls. It dies within three feet of the surface."

Garth caught the implication immediately. "Which means the stone above isn't stabilized by the resonance field."

"The cliffs are completely natural fracture planes," Penn said. "They aren't anchored to the buried matrix. If we plant chemical charges in the upper fissures, the resonance from the roadbed won't trigger an early detonation or cook the vitriol before the fuse burns. We can drop thirty tons of rimrock into the gap with four pounds of antimony paste."

Penn rolled the vellum tightly, slid it back into the leather dispatch cylinder, and tucked the cylinder into his own haversack alongside the field case. He picked up the courier’s maintenance kit, opening the tin clasp. Inside were twenty brass fuse-pins, three vials of sulfur-retardant oil, and a spool of varnished linen slow-match.

"The Red Kiln engineers were kind enough to supply the hardware," Penn said, slipping the tin into his belt pouch.

He stood up, brushing the red dust from his canvas trousers. He looked south toward the horizon.

Out in the wide, scrub-choked flats of the Barren Reach, a pale plume of dust was rising against the violet horizon. It was two miles back, creeping forward at the steady, relentless pace of heavy draft oxen and an eight-wheeled wagon.

"They’ll hit the mouth of the canyon just after dark," Garth said, his voice tightening. "If we're going to rig the throat, we have forty minutes to climb the rim."

"Then we don't waste ten of them talking," Penn said.

They left the gulley at a brisk jog, keeping to the shadowed western side of the ridge where the limestone bluffs blocked the sightlines from the highway.

The land rose sharply as they approached the northern barrier. The Barren Reach ended abruptly against a jagged wall of red-and-buff sandstone, sliced down the middle by a razor-thin canyon that looked as though it had been hacked out with a giant cleaver. That was Devil's Throat—the only passable wagon route through the border range for twenty miles in either direction.

At the base of the canyon wall, the highway was little more than a polished ribbon of dark granite wedged between two vertical walls of fractured stone. The air inside the gorge was dead, heavy with the smell of trapped heat and dry mineral dust.

Penn did not enter the canyon floor. He led Garth up a steep goat trail that wound through the jagged fissures on the western rim.

The climb was brutal. The sandstone was brittle, flaking away under their boots in sheets of red grit. Penn carried the weight of the field pack, the manganese-bronze tuning-strut pressing hard against his shoulder blades with every step. The dead man’s forearm bones, fused to the metal bracket inside the case, seemed to hold a strange, cold density, as if the ancient agony of their burial added physical mass to the iron.

Twenty minutes of hard climbing brought them to an overhanging shelf three hundred feet above the narrowest point of the canyon.

Penn crawled out onto the ledge, flat on his chest, and peered down over the edge.

The canyon floor below looked like a narrow trench. The road was barely wide enough for two freight wagons to pass hub-to-hub. Directly beneath them, on both walls of the gorge, deep stress fractures ran horizontally through the rock, where centuries of summer heat and winter freezing had separated the outer sandstone crust from the solid bedrock core.

"Here," Penn whispered.

He pulled the field kit from his pack. He unrolled three heavy canvas sleeves containing his chemical demolition paste—a volatile mixture of powdered antimony, refined vitriol crystals, and dried marsh peat.

Working with deliberate, steady movements, Penn measured out three ounces of paste into each of four copper priming tubes. His hands were completely still, despite the sheer drop three inches from his elbows. He knew the chemistry down to the grain: too much vitriol and the mixture would burn too fast, blowing outward into the empty air without cracking the rock; too little antimony and the reaction would produce only smoke and heat, leaving the fracture seam intact.

"Hold the fuse spool," Penn told Garth.

Garth gripped the varnished linen match, feeding it out inch by inch as Penn seated the brass fuse-pins into the priming tubes.

Penn took a long iron drift-punch and jammed the first copper tube deep into a natural vertical split in the shelf. He packed the mouth of the hole with moist clay from his pouch, tamping it down with the wooden handle of his hammer until the charge was sealed airtight.

He repeated the process three times along the ledge, linking the four tubes with a single continuous line of linen match.

When the last knot was tied, Penn sat back against the rock face, his breathing slow and measured. His palms were gray with rock dust, his fingertips stained with the pale yellow residue of vitriol.

Down in the lower draw, a mile south of the canyon mouth, the lead wagons of Fiona Brackett’s convoy emerged from the scrub.

Penn uncapped his brass spyglass and brought the lens to his right eye.

Through the gathering dark, the magnified image sharpened. The heavy outline of the rear freight wagon filled the circular frame. Behind it, tethered by its massive manganese chain, the Scale-Hound moved with a low, swinging gait, its armored flanks catching the pale glimmer of the rising moon. Beside the beast walked Hayes Carver, the handler’s broad shoulders hunched forward, his billhook swinging in his right hand as he scanned the blackening brush.

Garth knelt beside Penn, looking down at the approaching convoy. "We light the fuse when the lead team hits the bottleneck?"

"No," Penn said.

He looked down at the wagon, then across at the sheer wall opposite their ledge. The fracture lines on the far cliff mirrored the ones beneath their feet. If both charges blew simultaneously, the collapse would not just block the road; it would bury the entire gorge under two hundred tons of shattered caprock.

"We wait until Carver’s wagon enters the throat," Penn said, his voice flat and hard as the granite below. "If we drop the rock in front of them, Brackett turns the convoy around and retreats to the garrison. If we drop it on top of the rear guard, the beast is trapped in the rubble, the copper cargo is buried, and the road stays severed for three months."

Garth looked at him, a flicker of hesitation crossing his sharp features. "And Carver?"

Penn reached into his pouch, pulled out a flint striker, and laid it carefully beside the primed end of the linen match.

"Carver chose to drive a wagon on a road made of living bones," Penn said. He did not look at Garth. His eyes stayed locked on the dust rising below, tracking the heavy iron wheels as they rolled steadily into the mouth of the canyon. "He made his choice when he took Polk's clearance. Now he pays the toll."