The calibration track was eight inches of polished bronze, slick with oil and suspended sixty feet above the silvery mirror of the mercury sea. It shuddered violently with every rotation of the secondary gears, tilting beneath their boots like the deck of a schooner caught in a hurricane.
Silas kept his eyes fixed forward. He knew that to look down was to die.
Every instinct honed over twelve years of climbing the skeletal scaffoldings of the Upper Foundries took over. He calculated the oscillation of the track in his head: sway left two degrees, hold for three heartbeats, surge forward on the counter-revolution.
"Match my stride!" he yelled to Vesper over the whistling wind kicked up by the spinning wheels. "Don't fight the roll—lean into the torque!"
Vesper moved with an uncanny, instinctive grace despite her wounds. Her silver hair whipped wildly around her face, her eyes fixed on the floating crystal cradle ahead. Every time a rifle slug whistled past them, she didn't flinch; she simply lowered her center of gravity, her boots finding traction on the etched logarithmic spirals that lined the track.
Behind them, on the observation deck, Thorne had managed to haul himself back onto the platform with the help of his guards.
"Bring down the track!" Thorne’s voice roared through the cavern, amplified to a deafening thunder. "Concentrate fire on the central pivot! Drop them into the pool!"
The Praetorian riflemen shifted their aim. Instead of firing at the fleeing figures, they directed their heavy explosive slugs at the primary bronze gimbals supporting the calibration rail.
Pang! Thwack!
The iron projectiles struck the ancient bronze brackets. The metal groaned—an agonizing, high-pitched scream of shearing bolts. One of the secondary suspension cables snapped with the sound of a cannon shot, whipping through the air and gouging a deep scar across the granite ceiling.
The entire track dropped five feet beneath their feet.
Vesper screamed as her footing slipped over the edge. She fell, her arms flailing, but Silas dropped to his stomach, clamping his hand around her wrist with desperate force. The sudden jerk nearly dislocated his shoulder, his ribs slamming hard against the narrow track.
Vesper dangled in the void, her legs kicking over the churning mercury below. The Chronos Core, gripped in her other hand, flared with blinding violet light, its outer rings spinning so fast they sounded like a swarm of angry hornets.
"Silas!" she cried out, her fingers slipping against his oil-stained leather gauntlet. "I can't hold it!"
"Don't look at the pool!" Silas roared, his face turning purple with exertion as the muscles in his back tore under the strain. "Look at me! Look at the wrench, Vesper!"
He lunged his other hand forward, hooking his pneumatic torque wrench into the ring of her mail vest. With a primal roar of effort, he dragged her upward, inch by agonizing inch, until she scrambled her knees back onto the grooved bronze rail.
"The cradle!" she gasped, pointing ahead.
They were five paces away.
The central cradle was a marvel of translucent quartz, suspended inside four concentric rings that spun around three different axes simultaneously. It was the eye of the storm—the only stationary point in the entire roaring, spinning cathedral of gears.
Behind them, another suspension cable parted with an ear-splitting crack. The section of the track they had just crossed tilted ninety degrees, shearing off at the base and plunging into the mercury pool below. It struck the silvery liquid with a dull, heavy thud, splashing plumes of shimmering metal that hissed like acid against the lower rocks.
There was no track left to walk on.
"We have to jump!" Silas yelled.
"It's twenty feet!" Vesper protested, her face pale. "If we hit the gimbal rings while they're rotating, the blades will cut us to ribbons!"
Silas stared at the spinning gimbal rings. He watched the massive, razor-sharp speculum blades that turned around the cradle. To an untrained eye, it was an impenetrable wall of spinning metal. But to Silas, it was a twelve-interval escapement mechanism.
Tick. Tick. Tick.
Every fourth rotation, the three outer rings aligned for precisely half a second, creating an open corridor straight into the quartz cradle.
"Trust my timing," Silas said, taking the Chronos Core from her hands and tucking it securely under his left arm. He grabbed her hand with his right. "On three."
"Silas—"
"One!"
Behind them, Thorne’s riflemen fired another volley. A slug struck Silas in the left shoulder, tearing through the leather and flesh. A white-hot flare of agony exploded behind his eyes, but he refused to drop the Core.
"Two!"
The gimbal rings swept past, a blur of golden light and humming speculum.
"Three! JUMP!"
They launched themselves off the collapsing edge of the bronze rail into empty space.
For one terrifying heartbeat, they were weightless, hanging suspended between the ceiling of dark stone and the sea of liquid metal. The speculum blades rushed toward them, their razor-sharp edges reflecting the violet glare of the Core.
The alignment.
The three rings slid into place with a harmonic chime that resonated through Silas’s bones. They shot through the narrow, six-foot gap with inches to spare, the edge of a spinning counterweight catching the tail of Silas’s coat and ripping the cloth away like paper.
They hit the platform beneath the quartz cradle with a brutal, sliding crash.
Silas rolled onto his back, gasping for breath, his left shoulder numb and bleeding freely. Beside him, Vesper was already on her knees, dragging him toward the pedestal at the center of the crystal platform.
The cradle sat before them, its quartz socket glowing with a faint, expectant amber light.
Across the chasm, standing on the edge of the severed catwalk, Thorne watched them, his rifle lowered, his face twisted in disbelief and rage.
"Shoot them!" Thorne screamed, turning to his men. "Shoot the cradle!"
The guards raised their rifles, but they were too late.
Vesper placed both hands on the Chronos Core. Silas reached out with his uninjured right hand, covering her fingers with his own. Together, they pressed the pulsating brass sphere down into the quartz socket.
Click.
The sound was no louder than a watchmaker dropping a screw into a velvet tray.
Yet the moment the metals met, the entire mountain stopped.
The deafening roar of the drive shafts ceased. The massive planetary gears froze in mid-revolution, suspended in impossible equilibrium. The ripples in the mercury sea hardened into mirror-like stillness. Even the smoke from the rifle barrels hung frozen in the air like sculptured marble clouds.
A wave of pure, crystalline violet light erupted from the cradle. It washed outward in an expanding sphere of absolute silence, passing through Silas, through Vesper, through the cavern walls, surging upward through five thousand feet of iron, stone, and steam toward the High Spire of Oakhaven.
The clock had not been reversed.
It had been freed.