The wind at the summit did not just blow. It screamed. It was a physical force that sought to pluck Lyra and Caelan from the jagged ribs of the mountain. The air was so thin it felt like swallowing needles, and every breath was a battle. Lyra dug her boots into a narrow shelf of shale, her eyes squinting against the blinding glare of the morning sun on the fresh snow.
"There!" Caelan shouted over the roar of the gale. He pointed to a massive structure of rusted iron and stone that clung to the side of the peak like a parasite.
It was the headgate of the Black Pipe. It looked like a giant, open throat, wide enough to swallow a carriage. A series of heavy iron gears sat atop a stone platform, connected to a vertical shaft that disappeared into the depths of the mountain. This was the heart of the old flood system.
They scrambled toward the platform, their fingers numb despite their heavy gloves. The mechanism was a nightmare of neglect. Thick layers of orange rust had welded the gears together, and the grease from a previous century had turned into a substance as hard as diamond.
"It is frozen solid," Caelan said, his voice grim as he inspected the main drive wheel. He struck the iron with his wrench. The sound was flat and dead, like hitting a block of lead. "Even with the oil, we might not have enough leverage to break the seal."
"We have to try," Lyra said. She pulled the oil can from her pack and began to pour the dark, pungent liquid into the teeth of the gears. "If Sterling brings his troops through that pass, the city is lost. This is the only wall we have that he cannot climb."
Caelan nodded and braced himself against the primary lever. He was a man built for the forge, his muscles forged by years of striking hot iron, but the mountain was a different kind of opponent. He pushed with everything he had. His face turned a deep, dangerous purple, and the veins in his neck stood out like cords. The gear did not move.
"Help me!" he gasped.
Lyra threw her weight against the lever beside him. She planted her feet and pushed until her vision began to blur. She felt the iron biting into her palms through the leather of her gloves. For a long moment, the world was nothing but the smell of oil and the sound of her own straining lungs.
Then, a sound like a pistol shot echoed across the peak.
The first tooth of the gear had broken its bond. A shower of rust flakes flew into the air, caught instantly by the wind.
"Again!" Lyra cried.
They pushed in a rhythmic, desperate pulse. With every shove, the gears groaned a protest that sounded like a dying animal. Slowly, the massive vertical shaft began to rotate. Deep within the mountain, they heard a series of heavy, metallic thuds as the ancient counterweights shifted.
A low vibration began to hum beneath their feet. It started as a faint tremor and grew into a roar that rivaled the wind. Far below them, in the darkness of the pipe, the mountain runoff began to divert.
"The gates are opening," Caelan said, wiping the sweat and oil from his forehead. "If we turn it another three rotations, the pressure will be enough to wash the entire Sentinel Road into the valley."
Lyra looked down at the pass. From this height, the road looked like a thin, winding ribbon of gray. It was empty now, but she knew that would not last.
"Don't open it all the way," Lyra ordered. "We need to keep the threat in reserve. If we flood it now, they will just find another way. We need them to see the water. We need them to know that the mountain is awake."
Caelan eased his pressure on the lever, locking the gear in place with a heavy iron pin. The roar subsided to a steady, menacing growl. The Black Pipe was primed.
As they stepped back from the mechanism, Lyra noticed a small, bronze plaque bolted to the stone base. It was covered in grime, but she cleared it with her sleeve.
*Property of the Oakhaven Municipal Water Works. Designed by Thomas Belrose.*
Lyra felt a sudden, sharp pang in her chest. Her father had not just built the Spire and the clock tower. He had built the shield for the city. He had seen the dangers of the world and tried to give his people a way to defend themselves.
"He was always looking ahead," Lyra whispered.
"He was a man who understood the weight of things," Caelan said softly. He looked at Lyra, his eyes full of a new kind of respect. "You have his eyes, Lyra. But you have your own hands."
They began their descent as the sun reached its zenith. The trip down was faster, but no less dangerous. By the time they reached the lower slopes, the air was warmer and the smell of the foundries reached them once again.
When they entered the city limits, they were met by Silas. He was waiting by the trail head, his face pale and his eyes darting toward the harbor.
"The Coalition ships are moving," Silas said without preamble. "Graves moved the Vulture closer to the pier. And a second ironclad, the Talon, just arrived from the south. Sterling is on the deck of the new ship, and he is demanding to see you. He says the ten-day deadline is no longer negotiable."
"Why?" Lyra asked.
"Because they found the spies," Silas said. "Thorne's loyalists tried to sabotage the southern rail line. The Coalition thinks we are losing control of the city. They are using it as an excuse to move the Governor in tonight."
Lyra looked back at the mountain peak, where the Black Pipe sat like a silent sentinel.
"They want to move tonight?" Lyra asked, her voice turning to ice. "Then they are going to find out that Oakhaven has a very cold welcome waiting for them."
She walked past him toward the harbor, the oil of her father's machine still staining her skin. The clock had just run out of time.