"Get Node 5 locked at forty pounds," Danial repeated, his fingers tightening around the warm copper collar of his tool belt. "Tomorrow, we start digging the line to Node 6."
Maya didn't move away immediately. Her hand remained resting on the rim of her heavy tool pouch, her thumb absently tracing the brass bevel of her drafting compass. The white steam rising from the cracked floor plates drifted between them in slow, humid plumes, condensing into fine beads of moisture on the lapels of her leather coat.
"Node 6 is four levels down, Danial," she said softly, her eyes flicking up to the dark, cavernous mouth of Shaft 9 where the heavy elevator cables still hung taut and greasy in the gloom. "It's past the abandoned salt vaults. The Directorate hasn't maintained those conduits since the Great Lockout forty years ago."
"Then we clean the scale out of them ourselves," Danial said, turning his head toward the center of the platform where Gears was already unslinging a kerosene cutting torch from a wooden transport frame. "If we don't hold Node 6, Node 5 is just an island. Sterling can isolate the pressure loops from the central junction and starve us out in a week."
Gears slung the iron fuel cylinder over his shoulder with a heavy metallic clatter, wiping a smear of dark transmission oil across his chin. "Danial! The acetylene pressure is holding, but these burner nozzles are choked with carbon! You want me to cut the plow mounts first or burn out the track pins?"
Danial stepped across the wet iron plates, his heavy boots making loud, hollow splashes in the boiling runoff that still pooled in the depressions of the transit deck. "Cut the track pins on the lead crawler first, Gears. If Sterling sends a drop-wire down the shaft with an ignition charge, I don't want six tons of fueled iron sitting on top of our primary culvert."
"Got it," Gears grunted, striking a flint against the brass head of the torch. A bright, spitting blue flame erupted with a sharp WHOOSH, illuminating the soot-blackened belly of the Mark VIII Heavy Crawler.
Beside the dead vehicle, Miller was already barking orders at thirty scavengers from the Furnace Pit. They had slung thick hemp ropes over the armored roof of the second tender, using a salvaged Victorian chain-hoist to haul the vehicle's heavy steel side-plates away from the chassis.
"Mind the hydraulic lines, you thumb-fingered coal-shovelers!" Miller roared, pointing his short-barreled carbine at a young scavenger who was hacking at a bronze coupling with an iron hatchet. "That high-pressure oil isn't sewage—it's three-hundred-pound fluid! You nick that hose and it'll peel the skin off your arms before you can jump in the sump!"
The young scavenger pulled his hatchet back instantly, wiping his forehead with a ragged sleeve. "Sorry, Miller! The fittings are rusted solid!"
"Then use the kerosene solvent, boy!" Miller spat, stepping over a pile of sheared iron rivets. "We aren't scrapping this iron—we're turning it into a gatehouse!"
Maya walked up beside Danial as he knelt near the crawler's exposed drive housing. She unrolled a fresh sheet of heavy grid paper over the flat surface of an inverted tool chest, weighting the corners down with two heavy iron nuts.
"I've laid out the structural schematic for the Shaft 9 barricade," she said, tapping the drawing with a lead pencil. "If we cut the two Mark VIII armored plows free from their frame mounts, we can weld them directly into the mouth of the shaft archway at a sixty-degree wedge."
Danial leaned over the paper, squinting through the shifting steam at her precise pencil lines. "A sixty-degree angle... it'll deflect mortar fire from above."
"Exactly," Maya said, her pencil moving smoothly across the grid lines, adding a series of cross-hatched support struts. "If the Citadel drops high-explosive canister shot down the shaft, the angled iron will channel the blast wave outward into the granite side-chambers instead of down into our staging floor. But we need forty heavy anchor bolts driven into the bedrock to hold the wedge."
"Mother Cinder's crew has the air-drills," Danial said, looking toward the dark shadow of the archway where the old woman stood watching the work. "We can tap high-pressure air directly off the Node 5 auxiliary compressor. We'll drive the steel pins six feet into the basalt."
"What about the third tender?" Maya asked, looking back at the smaller armored vehicle sitting near the edge of the pit, its engine compartment completely gutted by Gears's crew. "The engine block is cracked, but the lower frame is solid."
"We turn the chassis into a stationary pump housing," Danial replied, reaching down to pick up a heavy brass flange from the scrap pile. "We mount the high-pressure water pump from the crawler's cooling loop onto the main culvert pipe. If Sterling tries to send infantry down the ladder tubes with flame-throwers, we can flood the entire vertical shaft with three-hundred-degree runoff in fifteen seconds."
Maya stopped her pencil, looking up at him through her dark lashes. Her expression was unreadable in the warm orange glow of the cutting torch. "You're building a fortress, Danial."
"I'm building a wall," Danial corrected quietly, his fingers tracing the cold brass threads of the flange. "The Citadel has lived behind stone and glass for three generations while the Sump froze. If they want to come down here now, they're going to have to break through their own iron to do it."
By five in the morning, the continuous roar of blue cutting flames and pneumatic drills had filled Sub-Sector 6 with a rhythmic, deafening tempo.
RAT-TAT-TAT-TAT-TAT!
The heavy pneumatic drills, powered by the roaring air lines from Node 5, bit deep into the black granite walls surrounding Shaft 9. Long plumes of pale gray stone dust rose into the humid air, mixing with the white steam to create a thick, chalky mist that hung over the entire transit deck.
Gears had successfully severed the massive, wedge-shaped armored plow from the front of the lead Mark VIII Crawler.
Using three heavy chain-hoists attached to the overhead crane girders, forty men were slowly dragging the three-ton slab of forged steel across the floor, its jagged lower edge screaming as it ground against the wet cobblestones: SCREEEEEECH!
"Hold the port tackle!" Miller yelled from his perch on an iron ladder. "Ease it down! Ease it down into the masonry slot!"
With a thunderous THUD that shook the stone floor beneath Danial's boots, the three-ton steel plow dropped into the newly drilled trench at the mouth of Shaft 9.
Immediately, six welders stepped forward with their heavy torches, their glass goggles flashing bright violet as they struck arcs against the iron, joining the plow's thick steel ribs directly to six-inch anchor bolts driven deep into the bedrock.
Bright showers of white-hot sparks rained down onto the wet floor, hissing as they hit the shallow pools of warm water.
Danial stood inside the newly constructed gatehouse frame, his shirt sleeves rolled up to his elbows, his hands covered in a mixture of dark graphite grease and white granite dust. He was holding a heavy sledgehammer, checking the alignment of a cross-brace that connected the plow plate to the secondary tender frame.
"It's three inches out of square on the left shoulder, Danial!" Gears shouted over the noise of the welders, holding a brass plumb-bob against the steel plate. "If we weld it like this, the strain will shear the lower anchor bolts when the metal cools!"
Danial set his feet on the wet stone, raised the eighteen-pound sledgehammer over his right shoulder, and brought it down against the edge of the steel brace with everything he had.
CLANG!
The heavy impact rang through the cavern like a church bell. The steel brace shifted half an inch to the right.
"Again!" Gears called out, watching the lead line.
Danial swung a second time.
CLANG!
"Hold it!" Gears shouted, watching the brass bob settle precisely over the scribed mark on the stone. "Perfect! Burn it in, boys!"
Two welders instantly stepped up, their bright blue flames spitting as they began lay down thick, ropy beads of molten steel along the joint.
Danial lowered the hammer, wiping his dripping forehead with his forearm. His lungs burned from the heat and the dust, but inside his chest, his heart beat with a steady, fierce rhythm. For the first time in his life, he wasn't fixing a broken pipe in a cold basement while waiting for an inspector to kick open the door. They were building something that belonged to them.
Maya walked through the swirling sparks, carrying a steam-heated iron kettle and two tin cups she had borrowed from Mother Cinder's kitchen.
"Drink this," she said, handing a cup to Danial.
The liquid inside was dark, hot, and smelled faintly of roasted chicory and dried mountain mint. Danial took a long sip, feeling the heat spread down into his chest.
"How are the pressure lines in Sector 4 holding?" he asked, looking past the sparks toward the dark tunnel that led back to Brimstone Alley.
"Oakes checked the main distribution header twenty minutes ago," Maya said, leaning her shoulder against the cool stone wall beside him. "The residential shafts in the middle blocks are sitting at eighteen degrees Celsius. People have opened their windows, Danial. For the first time in forty years, there's no frost on the inner glass of the tenement frames."
Danial looked down at his tin cup, watching the pale steam curl off the surface of the dark tea. "Did they find any more Directorate patrols?"
"None," Maya said. "The guards at the Shaft 4 transit office abandoned their posts when the heat hit the lower pipes. They thought the whole lower tier was going to explode. They took the upper lift cages and fled back to the High Glass district."
"They'll be back," Danial said softly.
"I know," Maya said. She reached into her coat pocket and pulled out the rolled parchment they had taken from the Citadel lieutenant—Special Directive 44. "Sterling can't hide a temperature jump of twenty degrees across three sectors. The environmental sensors in the High Directorate's council chamber are probably screaming right now."
Before Danial could answer, a loud, sharp whistle echoed down from the high gantry levels near the ceiling of the cavern.
FEEEEE-E-E-E-T!
It was the signal from the lookout post.
The wailing sound cut instantly through the roar of the cutting torches and the clatter of the drills. The welders extinguished their flames, dropping the cavern into a sudden, eerie half-darkness broken only by the flickering red glare of the fire-pots.
Miller instantly brought his carbine up, racking the brass bolt with a loud CLICK-CLACK, his eyes darting toward the dark vertical shaft of Shaft 9.
Danial dropped his sledgehammer, stepping past the newly welded plow plate onto the open edge of the transit platform. Maya was right beside him, her hand slipping into her coat pocket where her father's brass-cased pressure gauge rested.
Forty feet above them, on the highest iron catwalk hanging directly beneath the shaft mouth, a young scavenger named Finch was leaning over the railing, frantically waving an oil lamp back and forth in three wide, sweeping arcs.
" Danial!" Finch shouted down, his voice echoing hollowly through the long stone tube. "The upper cables! They're moving again!"
Danial jumped onto the steel frame of the captured tender, looking straight up into the pitch-black vertical tunnel.
High above—perhaps a thousand meters up in the dark—the six massive steel suspension cables were vibrating. Long, thin showers of rust flakes and dried grease fell down the shaft, flickering like red embers as they passed the lower lamp positions.
"Is it another lift cage?" Miller called out, his boots crunching on the gravel as he ran up beside Danial's vehicle. "Did they re-grease the winding drums?"
"No," Danial said, his eyes narrowing as he listened to the sound.
It wasn't the heavy, rhythmic CLACK-CLACK-CLACK of a six-ton freight cage descending on guide rails.
It was a higher-pitched, frantic metallic whine—the sound of a small, unweighted cable running through an unsheathed brass pulley at high speed.
Zzzzzzzzzzzzz-CLACK.
Something small, heavy, and metallic dropped out of the dark mouth of the shaft, falling straight down toward the transit platform.
"INCOMING!" Miller screamed, diving behind the newly welded steel plow.
The object didn't hit the floor.
Fifty feet above the platform, its descent was abruptly checked by a heavy steel braided cable. The object bounced twice in mid-air, swaying back and forth in the rising plumes of white steam.
It was an iron cylinder, roughly three feet long and eight inches thick, painted in bright, hazard-yellow diagonal stripes. Mounted on top of the cylinder was a brass clockwork timer, its internal gears ticking aloud with a sharp, rhythmic cadence: TICK-TICK-TICK-TICK.
From the base of the cylinder, a small nozzle began to spray a thick, sweet-smelling yellow gas into the rising thermal currents of the shaft.
"Masks!" Maya yelled, her voice muffled instantly as she pulled her leather respirator over her nose and mouth. "It's not an explosive! It's heavy sulfur-ether from the Directorate's chemical reserves!"
The heavy yellow gas didn't rise with the warm steam. Because of its extreme density, it immediately began to sink, tumbling down toward the staging floor in thick, suffocating folds like a golden waterfall.
"They aren't trying to blow the gate!" Danial shouted through his brass respirator, his voice sounding hollow and metallic inside the copper housing. "They're trying to clear the platform so their engineers can drop down on the secondary lines!"
The yellow cloud hit the transit deck, spreading rapidly across the stone floor and pooling in the low trenches where Mother Cinder's crew was still working.
Two scavengers who hadn't secured their respirator straps instantly dropped their picks, clutching at their throats as they fell to their knees, coughing violently in the sweet, choking mist.
"Gears! Open the Node 5 auxiliary vent!" Danial roared, jumping down from the tender and grabbing the long iron lever of the main air scrubber. "Flush the floor!"
Gears didn't hesitate. He threw his whole body against the secondary valve wheel, spinning it four turns to the right.
BOOM-HISSSSSSSS!
A massive jet of high-pressure, clean compressed air—diverted directly from the Node 5 pneumatic reserve—erupted from four floor nozzles surrounding the transit platform.
The roaring blast of clean air hit the dense sulfur-ether cloud like a giant broom. The yellow gas was instantly torn apart, swept upward into the high-velocity thermal draft of Shaft 9, and blown straight back up the long brick tube toward the upper city.
Up in the shaft, a muffled scream echoed down through the dark as the returning cloud of heavy yellow gas hit the Citadel advance team hanging on the secondary ropes three hundred meters above.
THUD! THUD!
Two iron grappling hooks, dropped by the upper team, lost their grip on the brickwork, falling down the shaft and slamming uselessly against the angled steel plate of Danial's new barricade before bouncing off into the deep sump.
Danial stood in the center of the platform, the roaring jet of compressed air sweeping his dark hair back from his forehead, his hand locked around the iron scrubber lever.
He looked up through the clearing air at the hazard-yellow cylinder still hanging from its cable fifty feet above.
"Maya!" Danial called out, his eyes bright behind his respirator goggles. "Hand me the cutting torch!"
Maya grabbed the long brass torch from Gears, handing it up to Danial as he climbed onto the top peak of the welded Mark VIII plow.
Danial raised the heavy torch, adjusted the oxygen flow until the blue cone of the flame was six inches long, and reached up toward the suspended iron cable.
The bright blue flame bit into the four-inch braided steel wire. Sparks erupted in a fierce, brilliant arc against the dark masonry of the ceiling.
CRACK-SNAP!
The cable severed.
The hazard-yellow cylinder, still ticking wildly, dropped like a stone into the yawning, five-hundred-foot abyss of the Deep Riser sump below, disappearing into the dark water with a distant, hollow PLOP.
Three seconds later, a low, muffled THOOM echoed up from the depths as the cylinder exploded underwater, sending a harmless plume of white foam rising through the drainage grates.
Danial lowered the torch, wiping the sweat and purple zinc flare from his goggles.
Silence fell over the transit platform once again, save for the deep, steady, beautiful hum of Node 5 working deep in the earth beneath their feet.
Miller crawled out from behind the steel plow, looking down into the deep sump, then up at Danial standing atop the three-ton iron wedge with the blue flame of the torch still spitting in his hand.
The old scavenger slowly unslung his carbine, setting the butt on the wet stone, and let out a long, low whistle.
"Well, Thomas's boy," Miller said through his respirator, his eyes creasing with a grim, fierce satisfaction. "I reckon Envoy Sterling just found out his broom don't reach all the way to the bottom."
Danial turned his torch off, the flame dying with a small pop. He looked down at Maya, who was standing at the base of the barricade, her oil lamp held high, illuminating the solid, unbreakable wall of iron and stone they had built in five hours.
"Gears," Danial said, his voice quiet, steady, and absolute. "Connect the air lines to the lower drills. We have seven hours before shift change... and Node 6 is waiting."