The orange flare of the torch sliced across Lin Ke’s eyelids like a dull blade.
His throat was bone-dry, coated in the metal residue of dried blood from his nosebleed. He didn’t blink. He didn’t shift his shoulders. Every muscle in his starved body went fully slack, mimicking the deep, dead stupor of a laborer who had spent fourteen hours hauling coke.
Overseer Fang’s heavy boots halted two paces from his straw mat.
The heat streaming from the pitch torch washed over Lin Ke’s face, competing with the cold draft leaking under the door. Above him, Fang’s breath came in ragged, wheezing gasps, smelling of sour garlic and stale sorghum liquor.
“Seven,” Fang grunted, nudging Lin Ke’s hip with the iron-shod toe of his boot.
Lin Ke let his head roll sideways, mouth slack, eyelids fluttering with convincing grogginess. He produced a hoarse, wet cough that rattled deep in his chest bone.
“Overseer...?” Lin Ke rasped, his voice thick with gravel. “Is it the morning bell already? The third tuyere... Did the pressure rise?”
Fang stared down at him, torch held high. The yellow flame lit up the dark circles bruised beneath the boy’s eyes, the hollow cheeks, and the soot smeared across his jaw. The overseer’s eyes flicked to the dark stain on the floor. Dried blood from Lin Ke’s nose, already caked with coal dust.
“You’re bleeding from the snout, brat,” Fang muttered, his suspicion hardened by familiar indifference. “The Iron Marrow is taking your lungs. You won’t last until the spring muster.”
“My chest... Burns, Overseer,” Lin Ke muttered, letting his eyelids droop. “Like hot sand.”
“Good,” Fang spat, turning his back. “Pain means the iron is taking root. Don’t die before dawn. Furnace Four jammed its clinker car. I need your eyes on the draft.”
The heavy footsteps moved away down the central aisle, the torchlight swaying toward the bunkhouse exit. The iron latch clattered shut, plunging the long room back into freezing, rotten-egg dark.
* * *
Lin Ke didn’t stay on the mat.
He waited ninety seconds, counting the rhythmic snores of the surrounding laborers until the baseline returned to normal. Then, moving with the slow, soundless economy of an engineer creeping through an active high-voltage power yard, he slid off the pallet.
His joints clicked—a dry, hardened snap in his right ankle that sent a cold jolt up his spine.
He slipped through the rear air-flow hatch near the wash basins, crawling out into the narrow, frozen alley behind the bunkhouse. The wind off the melted rock waste heaps was knife-sharp. It carried needles of frozen sleet that stung the fresh metal pen cuts on his thumb.
He couldn’t stay in the yard. Contraband sweeps were random, and if Fang caught him awake a second time, there would be no questions—only the copper whip.
Lin Ke slipped through an iron check grate into the disused soot chimney pipe of Kiln Three.
The chimney pipe was an upright shaft of crumbling heat-proof brick, three feet wide and thirty feet tall, abandoned decades ago. Just then, the lower smelting floor was swelled. It smelled of hundreds of years-old ash, damp stone, and dead sulfur.
It was dark, cold, and entirely isolated from human eyes.
He squeezed himself into a hollow nook where the draft dampers had long rusted away. He pulled his knees to his chin. The cold granite sucked the warmth from his thin linen trousers, grounding his trembling nerves.
Lin Ke leaned his head back against the soot-caked brick and closed his eyes.
Staging environment online.
The blackness of the chimney pipe dissolved. The phantom build materialized once more in the calm, silent void of his mind.
Eighty-two failures had mapped the terrain. Now came the stonework.
Step one: Heat generation.
The Nine-Fold Overclocked Crimson Spirit vein took raw Yang heat essence from the environment and pulsed it through the Sanjiao triple-burner channel. The problem was not the power source. The problem was that heat caused a cascading drop in channel flow pushback, resulting in an uncontrolled exponential runaway loop.
To counter heat runaway, every reliable system in existence used active cooling.
Step two: Counter-current loop.
Lin Ke traced the body lines of the phantom build. Directly next-door to the triple-burner channel ran the Kidney Shaoyin channel—the main living route for cold, Yin-dominant fluid straining.
In traditional manuals, mixing Yang fire and Yin water inside the same energetic side was considered heresy, an automatic trigger for spirit vein deviation.
Traditional elders don’t understand heat laws, Lin Ke thought coldly. They think fluids must touch to interact. They’ve never seen a shell-and-tube heat exchanger.
He didn’t mix the streams.
In the test model, he routed the cold Yin essence from the Kidney Shaoyin channel into an isolated, parallel bypass jacket wrapped around the outside of the Sanjiao channel. The cold fluid flowed in the opposite direction of the fiery Yang pulse.
A counter-current liquid cooling loop.
The white-hot Yang packet surged down the central glass waveguide. Then, the radiant heat excess was absorbed across the channel wall by the counter-flowing Yin fluid, moderating the core heat without diluting the packet’s moving punch.
Step three: Exhaust management.
Absorbing the heat was only half the solution. The heat energy had to go somewhere, or the kidneys would boil within minutes.
Lin Ke extended the exhaust run down the outward channels of both forearms. He ended the bypass loops directly at the center of his hands.
The Laogong acupoints.
The Laogong points were minor sense nodes used for acupuncture and pulse diagnosis. In Lin Ke’s refactored stonework, they were spring-loaded high-pressure blow-off valves.
The internal circuit heat crossed forty degrees. Each time, the end-post gates at the palms would dilate, releasing high-pressure heat waste directly into the air as white-hot air.
In the sandbox, the phantom drew a simulated packet of fire heat into its chest.
The fiery pulse hit the Sanjiao channel.
Instantly, the cooling jacket engaged. Cold Yin essence flooded the reverse-flow loop. It took in the heat spike in a clean, smooth-flowing slope. The core heat held at thirty-eight point two degrees.
The pulse reached the forearms.
The phantom’s hands opened. A controlled puff of high-pressure heat gas vented from both Laogong points with a sharp, sharp air hiss.
Lin Ke sat in the mental void, staring at the green text.
Three full cycles. No runaway loop. No burst heart. No boiled liver. The glassy glass channels handled the high-speed fire pulses with total, crystal-clear balance, their rigid walls serving as perfect, low-latency waveguides now that the heat swelling was controlled.
The stonework was sound. The unit tests had passed cleanly.
Lin Ke opened his eyes in the blackness of the chimney pipe.
The cold soot clung to his skin, smelling of ash and damp earth. His physical body was shivering from the winter draft. But beneath his ribs, his heart beat with slow, deliberate rhythm.
This is where the test model ends, he thought.
The Tian Fu was an extraordinary test tool, but it had one unbending, unforgiving boundary. It existed only in his mind.
There was no rollback in meatspace.
If his physical glass channels possessed a hidden micro-fracture from years of malnutrition, if his kidney Yin was too empty to sustain the cooling jacket, or if his manual dexterity slipped by a fraction of a tiny fraction of an inch while routing the physical current—he wouldn’t see an error code.
He would simply combust into greasy ash inside this abandoned chimney.
A live merge into production. Zero margin for error.
Lin Ke drew his iron metal pen from his waistband. He didn’t hesitate. He jammed the point into his thumb, pressing deep until the sharp pain cleared the lingering mental tiredness from his skull.
“Branch checked: main.”
He tucked the bloody metal pen into his sash, sat with his back straight against the soot-stained brick, and laid his calloused palms flat upon his knees.
He took a slow, deep breath of the freezing mountain air, filling his starved lungs.
“Tian Fu,” Lin Ke whispered into the dark of his own soul. “Merge to main.”