The moment they crossed into the tower, the world narrowed to darkness, ice, and the low groan of metal strained beyond its limits. The air was so cold it felt sharpened, carving the breath from their lungs as they stepped inside. Frost coated the inner walls like layered glass, so thick it seemed to swallow sound. Their footsteps echoed faintly, as if muffled by the tower itself.
Akihiro raised a hand, casting a small orb of white light. The glow flickered in the suffocating chill, but it was enough to reveal the spiraling staircase before them—narrow, steep, and half-consumed by crystalline growths twisting along the steps.
Omina tested the first stair with her boot. "This place is dying on the inside."
Fukashi whispered, "Or living. Hard to tell with mana growth this dense."
Yami moved her fingers through the air, feeling for currents. "The frost density increases with altitude. Whatever engine is at the top is compressing the mana field. We need to go slow."
Akihiro shivered as his Kindling Light spell guttered again. "If I lose the flame entirely… we might start freezing from the inside."
Yoshiya placed a steadying hand on his shoulder. "Stay close. The tower reacts to separation."
They began the climb.
The staircase wound upward, disappearing into shadow. Every step they took sent a ripple of frost dust drifting from the walls. Metal groaned within the structure—deep, painful, like an ancient creature straining against shackles. Sometimes the entire tower shuddered, and ice cracked in long jagged lines that crawled across the stone.
Halfway up, Omina exhaled and watched her breath crystallize mid-air, turning to snow-like powder before falling. "This isn't natural," she muttered. "Magic alone doesn't create frost that behaves like a living thing."
"Not magic alone," Fukashi replied. "It's being fed. Mana flow suggests something is powering the engine from below, not above."
Akihiro stopped briefly, closing his eyes. Kindling Light flickered low, then steadied as he drew deeper into his focus. "There's… pain. Below us." His voice trembled. "Not human. Not a machine. Something sealed. Something straining."
Yoshiya stiffened. "A creature?"
Akihiro nodded. "Its aura spreads upward. The cold is its breath."
They climbed faster.
By the time they reached the final landing, their limbs felt heavy, stiff from the biting air. Omina pushed open the iron hatch at the top, the door ringing like brittle glass. A wave of freezing wind rushed past them, tearing at their cloaks.
The chamber above was vast—far larger than the tower's exterior suggested. The walls curved outward, an unnatural expansion reinforced with metallic ribs. In the center of the room stood the Frost Engine.
It was monstrous.
A mechanical heart of gears, runes, and rotating rings, each layer spinning in slow, grinding rhythm. From its core erupted a pillar of white mana, blasting upward through the tower's crown. The air vibrated with every pulse, sending waves of frost washing out over the city.
Omina's hand went immediately to her hilts. "We stop it. Now."
Yoshiya seized her wrist. "No."
Her eyes snapped to him, sharp. "Yoshiya—"
"If you destroy that engine outright…" He forced breath into his lungs, fighting the cold. "The frost field shattering all at once would drop every frozen body into shock. They'd thaw too fast. Bones could crack. Hearts could stop."
Fukashi swallowed hard. "And the mana backlash might level half the city."
Yami stepped closer to the machine, her aura probing. "It's not just a device. Something is fueling it. Something bound directly below us."
Akihiro nodded, voice shaking. "I can feel the restraints. The aura is crying out… trapped… suffering."
A rumble shuddered through the chamber, sending a burst of icy wind spiraling outward.
The tower felt alive.
Yoshiya lowered Omina's hand but didn't release her wrist. "We can't break anything until we understand the system. The city is one heartbeat from collapse."
Omina's jaw tightened, but she stepped back. "Then we free the heartbeat."
The Frost Engine groaned again, frost spilling from its rotating rings. The team stood at the center of the mechanism's roar, staring into the heart of winter itself—knowing the real danger waited below.