The yellow sulfur pocket in the basalt wall did not merely burn; it screamed.

For a fraction of a second, the Great Chasm basin was painted in a blinding, chemical violet. The heat was a physical blow, a sudden wall of scalding air that instantly vaporized the freezing mist around the longboat. Then came the shriek—a high-pitched, pressurized whistle of trapped volcanic steam that had finally found an exit. The yellow crust of the basalt wall bubbled, blackened, and blew outward in a violent spray of boiling mud and shattered stone.

"Brace!" Cormac Reed roared, his voice instantly swallowed by the thunder of the blowout.

He threw his weight against the heavy oak tiller, but his right hand, wrapped in the stiff, blood-crusted crimson scarf of his late mother Maeve, failed him. The fingers, already numb and blistered from his grapple with Ragnar on the ice bank, refused to lock. The tiller kicked back like a striking serpent, the raw momentum of the river-surge slamming the heavy wooden handle directly into Cormac’s bruised ribs. The impact knocked the wind from his lungs, forcing him to his knees as a mountain of displaced water and ice-debris surged over the gunwale.

The *Ember* tilted violently to port, her copper-plated hull scraping against a submerged basalt shelf with a sickening, metallic screech.

"We're taking on water!" Toby Miller screamed from the mid-deck, his brass-rimmed spectacles lost in the dark as he clung to the main mast. The young cartographer was drenched, his heavy wool coat instantly saturated with freezing river water. "The current—Cormac, the blowout is pushing us directly into the Throat!"

He was right. The force of the steam explosion had created a massive, localized wave that propelled the longboat forward, driving them out of the basin and directly into the narrow, accelerating maw of the upper Frost-veins. The walls of the canyon closed in, rising hundreds of feet into the dark, their frozen faces glittering like jagged teeth under the faint, flickering blue light of the Hearth-Lantern.

From the engine hatch below, a new sound cut through the roar of the rapids: a sharp, rhythmic clanging, followed by the terrifying, high-velocity hiss of escaping steam.

"Cormac!" Garrick Vance’s voice was a desperate, muffled shout from the belly of the boat. "The boiler! The shockwave sheared the primary intake! The pressure gauge is redlining!"

Cormac struggled to his feet, his teeth grinding against the pain in his ribs and the dull, throbbing agony in his right hand. He looked down the engine hatch. Thick, white plumes of scalding steam were already billowing upward, filling the tight passageway with a choking, blinding fog.

"Rory! Gavin!" Cormac called out, lunging toward the hatch. "Get below! Check the hull welds!"

Rory Fletcher, the master carpenter, was already scrambling down the iron ladder, his leather tool belt clattering against the rungs. His son and apprentice, Gavin, followed close behind, carrying a heavy bundle of malleable copper thermal tubing and a soldering kit.

"The stern copper plates are holding, but the internal timbers are flexing!" Rory shouted over the din of the engine. His thick, calloused hands tapped the vibrating oak ribs of the hull, his eyes narrowed as he listened to the pitch of the wood. "It’s not the hull, Cormac! The steam line has ruptured below the waterline in the bilge! The cold river water is hitting the hot pipes—the welds are cracking!"

Cormac dropped through the hatch, entering the cramped, suffocatingly hot engine room. The air was thick with the smell of wet coal, sulfur, and hot grease. Garrick Vance was drenched in sweat, his broad shoulders strained as he fought to hold the primary steam bypass lever down. The brass pressure gauge on the boiler was redlining, the needle vibrating violently against the safety pin.

"I’m venting as much as I can through the exhaust," Garrick panted, his chest heaving. "But the bypass is choked. The cold water filling the bilge is freezing the drainage lines, and the pressure is backing up. If we don't seal that rupture in the primary line, the boiler is going to detonate. It’ll tear the *Ember* in half."

"We patch it! Now!" Cormac ordered.

Rory Fletcher pulled a thick strip of grease-soaked canvas from his belt, wrapping it tightly around the visible crack in the primary steam line. "Hold the collar, Gavin!" he barked.

But the moment Gavin stepped forward to secure the wrap, a violent surge of high-pressure steam tore through the canvas, shredding the thick material into charred ribbons. The scalding jet missed Gavin's face by inches, hissing violently as it struck the damp timber of the hull.

"It’s no use!" Rory cursed, wiping hot moisture from his eyes. "The pressure is too high for canvas! We need to bypass the damaged section entirely. Gavin, where is that thermal tubing?"

"Here!" Gavin Fletcher pulled a length of malleable copper thermal tubing from his bundle. "But we can't weld it while the line is pressurized, and the manual release valve is submerged in the bilge!"

Cormac looked down. The bilge was a dark, freezing pool of river water and slush, rising rapidly over the deck plates. The water was black, choked with coal dust and oil, and it was cold enough to freeze flesh in minutes. The manual release valve—the only way to isolate the ruptured section and allow the copper bypass to be installed—was located at the very bottom of the bilge, beneath three feet of ice-slush.

"I’m going in," Cormac said.

"Cormac, no," Garrick said, his grip tightening on the redlining bypass lever. "That water is straight from the glaciers. You plunge your hand in there, and you won't feel it again."

"If the boiler blows, none of us will feel anything again," Cormac replied, his voice flat, devoid of hesitation.

He did not have his diving suit on; there was no time to bolt the heavy brass collar or secure the double-paned helmet. He wore only his caribou-skin coat and his woolens. He knelt on the wet floorboards, looking down into the black, oily water of the bilge. The water reflected the faint, chaotic orange glow of the boiler furnace, looking like a pool of liquid obsidian.

Cormac reached down with his right arm. The moment his hand broke the surface of the bilge, the cold hit him like a physical blow.

It did not feel like cold; it felt like fire. A thousand liquid needles drove deep into his skin, piercing through the layers of Maeve’s crimson scarf and biting directly into the raw, ruptured blisters on his fingers. The pain was so intense, so sudden, that his vision went momentarily black. His lung, scarred from his past failed expedition, seized up, cutting off his breath.

*"Breathe, Cormac,"* Alistair’s voice whispered in his memory. *"Slow the lung. Don't fight the chill. Let the blood stay in the core."*

He forced his diaphragm down, taking a slow, shallow breath of the sulfurous engine room air. He pushed his arm deeper into the freezing slush, his fingers searching blindly through the dark pool for the brass collar of the manual release valve.

The water was thick with coal grit, scraping against his skin like sandpaper. He found the valve pipe, his numb fingers sliding down the cold metal until they brushed against the heavy, T-shaped brass handle.

It was rusted, frozen in place by years of neglect and the creeping chill of the deep.

"Gavin!" Cormac rasped, his teeth chattering so violently he could barely form the words. "The... the valve is seized. I need... leverage."

Gavin Fletcher scrambled forward, sliding a heavy copper spanner wrench into Cormac’s left hand.

Cormac submerged his left arm as well, the double onslaught of the sub-zero water sending a violent shudder through his entire frame. His heart hammered against his ribs, a frantic, irregular rhythm as his body fought to maintain its core temperature. He aligned the spanner with the valve collar, but his right hand had lost all sensation. The fingers were pale, stiff, and completely unresponsive, looking like the hands of a corpse beneath the dark water.

He could not grip the wrench with his right hand. He could not turn the valve with his left hand alone.

In desperation, Cormac leaned forward, submerging his face to the jawline in the freezing bilge. He locked his teeth onto the cold brass collar of the valve, using the strength of his jaw and his neck muscles to assist his left hand as he threw his weight against the spanner wrench.

The metal ground against metal. For a terrifying second, nothing moved. The boiler above them groaned, a low, ominous vibration that shook the entire hull.

"Cormac!" Garrick screamed. "She’s going to blow!"

With a final, agonizing heave, Cormac threw his entire body weight to the left.

Beneath the oily water, the seized brass valve finally yielded. It turned with a sharp, metallic *clack*, isolating the ruptured steam line.

"Pressure is dropping!" Garrick yelled, his eyes fixed on the brass gauge. The needle swung backward, retreating from the redline and stabilizing near the safe margin. "It worked! Gavin, get that bypass in!"

Gavin Fletcher moved with practiced, frantic speed. He slid the malleable copper thermal tubing over the isolated section, using his specialized wrenches to crimp the copper collars into place. The soft, ductile metal conformed perfectly to the uneven contours of the old-world steam line, creating an airtight seal that bypassed the cracked weld.

"Bypass is secure!" Gavin shouted, wiping sweat and grease from his forehead. "Garrick, slowly engage the draft!"

Garrick eased the bypass lever back, his eyes locked on the new copper line. The tubing hummed, expanding slightly as the hot steam surged through it, but the seals held. The clanging in the engine room subsided into a steady, rhythmic thrum.

Below deck, the crisis was averted. But on the wet floorboards of the bilge, Cormac Reed lay motionless.

Garrick and Rory hauled him out of the freezing water, dragging his shivering body onto the dry mid-deck. Cormac’s skin was a pale, bluish-gray, his lips white, and his entire body was locked in a violent, uncontrollable tremor.

"Get his coat off!" Rory barked, reaching for his knife to cut the frozen caribou skin.

"No," Cormac whispered, his voice a faint, rattling wheeze. He struggled to sit up, his left hand clutching his chest. "The... the tiller. Who has... the tiller?"

"Toby has it," Garrick said, kneeling beside him and wrapping a dry caribou-skin blanket around Cormac's shoulders. "We're in a slow-moving channel now, Cormac. The rapids are behind us for a few miles. You need to get warm."

Garrick reached into his vest, pulling out *Declan's Coal Hand-Warmer*—the small, pocket-sized brass furnace that burned crushed coal dust. He ignited the slow-burn wick, the small device emitting a faint, steady heat and a thin trace of sulfurous smoke. He placed the warm brass cylinder directly into Cormac's left hand.

"Hold onto it," Garrick said quietly.

Cormac looked down at his right hand. He slowly unwrapped the stiff, frozen crimson scarf.

The skin of his fingers was a stark, waxy white, mottled with dark, purplish patches of severe frostbite. He tried to flex his index finger, but there was no response. The nerves were dead, the tissue deeply damaged by the prolonged exposure to the sub-zero bilge water. The jagged scar across his jawline throbbed with a cold, hollow ache, a mirror to the permanent numbness that had settled into his hand.

He had saved the boat. He had kept the boiler from detonating. But as he stared at his useless, frozen fingers, Cormac knew the cost.

He was a cave-diver who could no longer grip his own ropes.