The Draft

The Fourth Terrace smelled of damp wool, sulfur, and panic.

I hit the landing at the bottom of the descent chute with both boots skidding through red volcanic mud. Yamato landed behind me with a grunt that rattled the stones underfoot. Around us, three hundred refugees from the upper tier were packed along the basalt walkway, huddled over brazier grates that were barely holding an amber glow. The main draft from the breached northern rim had not flooded the open walkways yet, but the air tasted thin, salted with soot and cold river mist.

A wall of stacked basalt blocks blocked the main ramp leading to the lower flues. Four men in boiled-leather cuirasses guarded the opening, their spears tipped with crude iron rather than obsidian.

"Halt," the tallest guard barked, leveling a shaft at Yamato's chest. "Nobody passes through the barricade without Kento's mark."

Yamato did not slow down. He took one heavy step forward, his chest heaving, his lavender-chilled daggers still clutched in his thick fists. "Out of the way, Jiro. Soshi's vanguard is already tearing through the Third Terrace. If you want this gate to stand ten breaths, you let us through."

The guard glanced at Yamato's daggers, then at the tool-roll across my shoulders. His posture shifted from defensive to predatory. "A knapper. Kento wants every toolmaker brought to the armory immediately. Move."

They ushered us through a gap in the stone rampart and down a narrow alleyway flanked by squat stone dwellings. At the end of the corridor stood the terrace storehouse, a low bunker built over a natural steam fissure. Inside, iron lamps sputtered against the walls, casting greasy yellow light over stacks of wooden crates and dozens of weapon hafts stripped of their heads.

Kento stood by the central hearth. He was a broad-shouldered man with gray-streaked hair bound in a tight knot and arms scarred from decades of pit matches. He wore an iron-studded breastplate and held a notched cleaver across his knees.

"Yamato," Kento said, not rising from his stool. "I heard your match got canceled. Along with half the northern rim."

"The whole upper ring is gone," Yamato said, dropping onto an empty bench. "Soshi's raiders have ice on their wicker shields. Our thermal blades are snapping like dry twigs."

Kento's gaze moved to me, lingering on the grease-stained sheepskin harness strapped tight against my ribs. He did not know six prime, insulated cores rested beneath the leather, and I had no intention of enlightening him.

"You are Tadashi," Kento said. It was a statement of utility. "The knapper from the vent line."

"I am," I said. "And my workshop is currently buried under frost. If you have an open hearth with decent draft, I have tools."

"You have work, not tools," Kento corrected, gesturing with his cleaver toward three large wicker baskets in the corner. "The Third Terrace fell because nobody had enough glass to hold the stairs. I have sixty fighters at the barricade and twenty more on the flue ladders. I need eighty thermal broad-knives knapped, bound, and heat-soaked before the second watch."

I looked at the wicker baskets. They were piled with black, glassy nodules the size of a man's skull, dug from the terrace quarry pits.

"Eighty knives," I said flatly. "With what stone?"

"That stone," Kento said. "Two hundred pounds of raw volcanic glass. Harvested from the eastern quarry shelf three days ago."

I walked over to the nearest basket and picked up a nodule. It was dark, glossy, and heavy in my palm. To an untrained fighter, it looked like masterwork material.

I drew my bone billet from my belt. I did not strike the nodule. I tapped the base of the antler billet against the stone's flat striking platform, letting the shockwave pass through the conchoidal structure.

The stone did not sing. It buzzed with a dull, rattling vibration that died in half a beat.

"Dead," I said, tossing the nodule back into the basket. It struck the pile with a soft thud.

Kento's eyebrows drew together. "What are you talking about? That stone was quarried before the raiders even hit the rim."

"The stone was brought down from the upper quarry shelf," I said, wiping cold moisture and basalt grit from my fingertips. "When the northern rampart collapsed, the freezing arctic air dropped straight down the storehouse's upper exhaust vents into this warm room. Rapid thermal contraction put micro-fractures through every brittle nodule in this basket. You can knap an edge onto it, sure. But the moment you heat-soak it in a hearth, the thermal shock will split it down the fault lines."

A murmur went through the four guards at the door. Yamato leaned forward, his heavy brow furrowing.

"Show me," Kento demanded, his voice dropping into a dangerous rumble.

I picked up the nodule again. I placed the tip of my copper punch against the edge, set the angle to forty-five degrees, and brought the billet down with a controlled tap.

A proper core would have yielded a long, razor-thin prismatic blade with clean conchoidal ripples. Instead, the nodule split into four jagged chunks, crumbling along internal white stress lines into useless gravel.

"You see that white grain?" I held up a fragment for Kento to inspect. "Internal shear. If your fighters take this into the choke point, their weapons will shatter on the first swing. You won't be holding a barricade. You'll be feeding sixty men into Soshi's spears."

Kento stared at the shattered fragments on the dirt floor. The vein in his temple pulsed once, hard. "That is the only stockpile on the Fourth Terrace. If this stone is ruined, we have nothing to arm the line."

"The quarry stone is ruined," I agreed. "Because it sat where the freezing air could touch it."

"Then where do we get glass?" Yamato asked, his voice strained. "The upper terraces belong to Soshi now."

"Down," I said. "The deep flues."

Silence settled over the storehouse, thick and suffocating. The deep flues were the primary geothermal arteries running beneath the crater floor, feeding heat to the entire city. They were also unmapped, toxic with sulfur vents, and strictly barricaded by city law to prevent miners from triggering cave-ins.

"The flues are sealed," Kento said slowly. "The air down there burns a man's lungs in fifty breaths."

"The air burns because the flues are hot," I replied. "And because they sit under two miles of solid basalt, the freezing surface drafts never touched them. The glass in the deep chimneys is pure, unshocked, and already sitting at thermal saturation. If you want eighty knives that will actually cut raiders instead of breaking in your fighters' hands, that is the only place to harvest them."

Kento studied me, his scarred hand tightening on the hilt of his cleaver. "You want me to open the flue gates."

"I want three things," I said, holding up three fingers. "First, unseal the iron grate to the primary flue. Second, I take Yamato with me to haul the heavy nodules. Third, when I bring the cores back, I get full, unrestricted access to your main forge hearth, and no one touches my finished blades until I set the trade value."

Yamato grunted in approval, shifting his bulk off the bench. "I know the lower chimney tunnels, Kento. I hauled ore down there when I was sixteen. I can keep him alive."

Kento stood up from his stool, towering over me. His iron breastplate clinked against his belt. For a brief span of breaths, the only sound was the hiss of steam rising through the floor vents.

"If you do not return with fifty pounds of prime core before midnight," Kento said, his voice flat as an executioner's slate, "I will bar the flue gate from this side and let the gas take you."

"Fair enough," I said, slipping my billet back into my belt. "Give us two damp respirators and an iron chisel."

Ten minutes later, Yamato and I stood before the heavy iron hatch that opened into the deep flues. Below the rusted grate, a steady, rhythmic rumble vibrated through the stone, carrying the thick stench of sulfur and the red-orange glow of living magma.

Kento's guards hauled the iron lever back with a loud clank, unlatching the hatch and letting a wall of dry, sweltering heat roll out across our boots.

I adjusted the sheepskin harness around my chest, keeping my salvaged cores snug against my ribs, and took the iron chisel from Yamato.

"Don't take too long looking at the rocks down there," Yamato said, pulling his damp cloth mask over his mouth and nose. "The air tastes like roasted copper, but at least nobody's throwing ice at us yet."

"Keep the sack ready," I said, checking the bite of the chisel against my palm. "We only need fifty pounds to make Kento smile, but I intend to carry out sixty."