The sub-zero freeze dropped upon Grey Crag not as a gentle winter frost. But as an arctic hammer that turned the mountain air into a haze of suspended ice needles. By nightfall, the liquid silver in Giles’s alcohol thermometers had dropped past twenty-four degrees below zero.
Across the residential insulae and barracks, the settlement was in agony. Sleet howled horizontally through narrow alleys, freezing gutters solid and sealing wooden doors behind sheets of jagged ice. Inside the stone apartments, five thousand refugees and pioneers huddled around sputtering fire bowls. It shivered beneath damp wool blankets as their breath froze against inside walls.
Down in the underground aqueduct vaults beneath the central citadel, a sharp BANG echoed through the stone foundations.
Giles Croft, bundled in his fur-lined wool greatcoat with sheepskin work mittens, crouched beside an exposed water channel. A six-inch cast-iron pipe had split along its lengthwise seam, burst by the irresistible volume spreading of freezing water. A solid metal tube of white ice protruded from fractured iron like marrow from a broken bone.
Before Giles’s eyes, a red-bordered emergency pane flickered into sharp focus.
“A forty-two percent public works failure in four hours,” Giles muttered, checking the fractured iron casing with a steel probe. “Freezing water expands by nine percent in volume, exerting up to thirty thousand pounds of pressure of water-pressure hoop stress against pipe walls. You can’t fight heat laws with thicker cast iron.”
“Lord Giles!”
Captain Kenneth Drake dropped the stone stairs into the vault, breath billowing like smoke. His woolen tunic was frosted white, his scarred face dark with tiredness.
“The woodcutters can’t venture into the lower pine woods,” Kenneth rasped. “Two wagon drivers suffered third-degree frostbite. Hearths in District Three are burning their final cords of firewood. If we don’t supply fuel by morning, the old folk and babes will freeze in their cots.”
“Burning cordwood in open hearths is an atrociously inefficient heat-powered cycle,” Giles said. He rose and picking up his brass tone check hammer. “An open stonework fireplace has a heat smooth speed below fifteen percent. The leftover eighty-five percent vents straight up the chimney pipe, pulling cold outdoor draft across the floor through heat-rising sneaking. Burning timber to heat five thousand people in a blizzard is a rapid path to total settlement collapse.”
Kenneth blinked, rubbing his numb ears. “Then... What fuel do we burn?”
“We don’t burn anything,” Giles replied. He tapped his hammer against the dark fiery dark rock floor.
CLINK... THUMMM.
The heavy, ringing ring shook through the rock with a deep, low-hum.
“Grey Crag sits atop an active fiery fault line,” Giles said. He pulled a deep-rock survey map from his satchel. “Eighty meters beneath this floor lies a high-pressure hot-water fissure. White-hot underground steam trapped beneath a capstone of dense dark rock. Heat levels exceeding one hundred and eighty degrees under forty sea-weights of pressure. We’re sitting on an infinite town heat battery. We’re freezing to death because no one bothered to sink a tap.”
Master Borin Bronze-Lung trudged into the vault, leading a team of eight dwarven smiths pushing a huge wheeled iron frame loaded with heavy machine parts.
“The core drill is assembled, Lord Master builder!” Borin bellowed, copper beard frosted with rime. “We cast the diamond annular crown just as your schematics ordered! But drilling through eighty meters of mountain dark rock... Lord Giles, that would take an old family clan three seasons of chisel work!”
“It takes three seasons if you chisel by hand like an unmodded peasant,” Giles said, stripping off mittens and picking up a three-foot pipe wrench. “It takes three hours if you apply clockwork rotary torque.”
In the center of the vault, the team erected the heavy drilling derrick. Four massive squared-pine timbers formed an A-frame over the marked drilled shaft, heavy with forged steel tie-rods. At the apex hung a cast-iron traveling block and rotary swivel.
Below it, mounted to a timber foundation bolted to the bedrock, sat the rotary drive table. An edge-gear assembly connected by chain drive to a two-metal tube back-and-forth steam engine fed by the foundry’s backup boiler.
Toby Karr rolled out the centerpiece of the drill string. A hollow, eight-inch annular coring bit forged from hard dark metal steel. Its cutting face was studded with heavy-duty diamonds, crushed black glass chips, and sintered heavy dark metal teeth set in a nickel-bronze matrix.
“Thread the first twenty-foot drill stem,” Giles ordered, checking grease seals. “Toby, connect the cold-water flushing pump. If the bit runs dry, frictional heat will melt the bronze matrix in forty seconds.”
“Flushing pump connected, Lord Giles!” Toby cranked a bronze pump, forcing a high-pressure jet of cold water down the hollow drill pipe.
Giles stepped to the throttle, pulling the lever back with a firm click.
CHUG-CHUG-CLACK!
The steam engine hissed and groaned, twin pistons pumping with furious power. The overhead edge gears meshed with a deep clockwork growl. It spun the four-inch steel drill pipe at one hundred and twenty turns a minute.
Giles engaged the feed clutch. The diamond annular bit touched the dark stone floor.
SCREEEEEECH!
A bone-jarring clockwork shriek tore through the vault as diamond teeth bit into fiery rock. The stone floor trembled beneath their boots. Crushed grey stone slurry gushed out of the drilled shaft collar, washing into the drainage sump in a steady torrent.
Borin Bronze-Lung stared at the sinking drill stem, eyes bulging in disbelief.
Foot by foot, the steel pipe dropped into solid rock. Where a dwarven pickaxe would have shattered against glassy dark rock, the spinning diamond crown chewed through stone at two feet every minute.
“Ancestors preserve us...” Borin whispered, pressing hands against the shaking timber derrick. “It cuts mountain rock like hot iron through cheese!”
Sister Teresa arrived at the landing above. She grabbed an iron crucifix and war-mattock, watching the spinning shaft go down. The roaring clockwork shriek, smell of crushed rock, and geysers of grey water filled the cave with intensity.
“The Descent into the Deep pit!” Teresa cried out, eyes shining with zeal. “The Lord Master builder pierces the crust of the underworld! He commands underground fires to surrender heat to the righteous! Blessed be the bore that breaks the deep stones!”
“Sister Teresa, stand back from the rotary table,” Giles shouted over the din. “If your habit catches in that spinning edge gear, it will wrap you around the drive shaft in half a second. Occupational safety doesn’t take religious holidays.”
Twenty feet down. Forty feet.
Toby and Borin hoisted a second drill stem into the derrick, spinning square-threaded Acme couplings together with chain tongs before Giles re-engaged the throttle.
At seventy meters, the slurry gushing from the drilled shaft began to steam. Return water heat rose rapidly—forty degrees, sixty degrees, then boiling hot. A low, underground rumbling echoed from deep within the rock, with the smell of fiery sulfur.
Giles watched the mud pressure gauge. The liquid silver column was rising fast.
“Slurry heat ninety-two degrees,” Giles reported with sharp focus. “Formation pressure increasing. We’re through the dark rock capstone. Toby, Borin—swing the blowout preventer over the casing pipe right away!”
The smiths lunged forward, sliding a four-hundred-pound cast-iron gate valve over the surface casing and bolting the flanges tight with heavy steel studs.
At eighty-two meters, the drill string gave a sudden downward lurch. The bit broke into empty space.
CRACK-THOOOOOM!
The bedrock beneath their boots bucked wildly.
An ear-splitting roar erupted from the drilled shaft like freight trains screaming through a tunnel. Flushing water was blown out of the pipe. It was followed by a huge geyser of white-hot, dry underground steam blasting upward with terrifying force.
The pressure slammed against the iron casing with a screech. High-enthalpy vapor hissed from relief fittings. It filled the vault with a blinding fog of pure, clean heat.
Borin and the dwarf apprentices threw themselves flat against the floor, shielding their faces in terror.
Giles stood upright before the roaring casing, fully calm. He pulled heat-resistant gloves onto his hands. He stepped into the whistling vapor and gripped the three-foot cast-iron handwheel of the blowout pipe hub.
With steady, calculated force, Giles cranked the wheel clockwise.
SCREEE-CLANK!
The heavy bronze wedge gate seated inside the valve body, choking the wild vent. The roaring geyser subsided into a controlled, high-pressure scream, channeled safely into the six-inch padded spreading pipe hub along the vault ceiling.
A brilliant amber pane ignited in the center of Giles’s vision.
Giles turned the backup spreading valve. “Diverting main steam to the town loop. Toby, open the main steam bypass into the district channels.”
“Opening bypass!” Toby threw the iron lever.
Deep within the underground arched concrete sewers running beneath the Macadam avenues of Grey Crag, four miles of padded double-walled steam mains filled with scalding steam. Heat traveled through pipe galleries directly into basement heat exchangers of residential insulae, hospitals, barracks, and outer edge casemates.
Up on the surface, warmth radiated through thick concrete slab floors. Within thirty minutes, frost coating stone window casements melted into clean rivulets of warm water. Air heat inside the apartments rose from freezing to a balmy sixty-nine degrees Fahrenheit.
Refugee mothers cried with relief as children peeled off sodden sheepskin cloaks. It walked barefoot across warm stone floors that felt like summer paving.
In the militia barracks, hardened border veterans stood in awe around cast-iron radiator banks, warming calloused hands over whistling metal fins without a puff of woodsmoke or ash.
Sister Teresa walked heated avenues. She murmured fervent blessings at warm air venting from brass radiator grates. “The breath of the living earth... Summoned by the Lord of Measures to conquer frost! The winter is broken!”
An hour later, Giles stood on the open low roof wall of Bastion Alpha.
The northern blizzard still shrieked across the cliffs, but from the central citadel tower, a massive column of clean white steam rose into the frozen night sky, lit by the moon like a blazing bright pillar.
Giles leaned against the granite merlon. He held a tin mug of chicory tea brewed on a steam tap, savoring a hot sip.
“Radiant floor heating with zero fuel consumption,” Giles murmured. “Smooth speed rating ninety-six percent. Finally, decent outside controls.”
Kenneth Drake stepped onto the low roof wall beside him, brass telescope leveled toward high ice-slow peaks to the north. His expression was grim.
“Lord Giles,” Kenneth whispered. “Look to the northern crests.”
Giles raised his sighting scope, training thirty-power optics across snow-choked mountain passes three leagues distant.
Through the crosshairs, lit by moonlight and the glow of Grey Crag’s steam plume, huge shadows moved across the glaciers.
Towering thirty feet into the gale, draped in hides of woolly mammoths and wielding tree-trunk clubs studded with ice-slow ice, a horde of huge figures dropped the mountain pass. At their head strode a titan crowned with jagged blue ice crystals, his glowing eye fixed on the warm steam plume rising from Grey Crag.
A low, earth-shaking roar shook the northern ridges, shaking through the castle foundations.
“Frost-Giants,” Kenneth whispered, grip white on his pacing pole. “Chieftain Ymir-Krag and the Clan of the Glacial Maw. They have seen our steam... And they’re coming to drown the hearth in blood.”
Giles took another sip of tea, lowered his sighting scope. Then he looked down at the five-pointed star castle and its newly installed rotary shard-cannons.
“Frost-giants with wooden clubs and zero understanding of enfilade crossfire,” Giles said calmly. He set his mug on the stone coping. “Good. The heavy infantry test phase begins at dawn.”