[ ZONE: Celestial Tower Base — Core High-Pressure Cooling Ring ] [ ENVIRONMENTAL PARAMETERS: Ambient pressure: 800 MPa | Ambient temperature: -269°C (liquid helium superfluid state) | Logic pressure: 0.00% ]
This was not piloting. This was being compressed by an invisible hand at the bottom of an ocean that had no surface.
The instant they entered the cooling ring, the external hydrostatic pressure — 800 megapascals — descended on the Stray Dog frame like a mountain in the process of collapsing. The armor's interior produced a sound of metal stress that registered in the teeth before the ears — every weld seam, every fastener articulating under a force sufficient to compress carbon atoms into diamond lattice.
"Yi — skeletal pressure — at critical threshold —" Chen Changsheng's voice inside the extreme-pressure cabin was fragmenting as it reached her, the specific dryness of lung air being over-compressed. "—"
"Activate Heaven's Bone phase-change suppression." Yi was folded into the secondary seat, her body encased in the anti-compression fluid, reduced to issuing commands through the neural uplink — physical movement was no longer an available option.
The liquid metal injected into the armor's structural cavities triggered its terminal Non-Newtonian defense response under the extreme pressure load: the more violent the compressive force applied, the more violently the intermolecular repulsion forces within the material escalated in return. The armor's exterior shell — which had been on the edge of buckling inward — was held open by the silver structural network, a survival space forced into existence against the physics trying to close it.
They were inside Zero's bloodstream.
Surrounding them: liquid helium in superfluid state — zero viscosity, effectively zero friction — carrying the Stray Dog on the residual thrust of the Planck Engine's detonation at a velocity that the cooling ring's designers had not considered when they calculated what could survive inside it.
"Zero has detected us." Yi said this at the level of internal monologue.
Ahead, the deep blue liquid helium layer — previously undisturbed, quiet as something that has never been touched — began producing concentric disturbance patterns.
Zero's logic signal could not propagate into this environment. But he retained physical control of the mechanism around them. He activated the Gravity Anchors positioned along the base structure's mid-section.
In physics, gravity is the one force that penetrates every shielding configuration without attenuation.
"Warning: localized spacetime curvature anomaly detected." The armor's physical detection instrument threw red across every display surface simultaneously.
Ahead of them in the conduit, the liquid helium began converging toward discrete center points — forming a series of small, extremely high-density gravity wells. Each one was a mouth open in the path of their travel, configured to seize the armor, compress it against itself, and drag the residue down into the waste processing infrastructure below.
"He's redistributing mass concentration." Chen Changsheng was working the thrust vector control against a resistance that the control system was not designed to overcome. "We're being pulled in —"
One of the Stray Dog's mechanical arm sections reached the edge of a gravity well. The steel plate there deformed — not fracturing, not cracking — curling, the way paper curls near a heat source.
"Do not fight the gravity." Yi's voice was operating at the upper boundary of what the compression on her chest allowed. In this moment her consciousness had completed a deep synchronization with the Planck Engine's operational state — she could feel the residual energy reserves in its architecture the way a person feels the muscles in their own body. "Changsheng — cut main thrust. Engage angular momentum compensation. We use these gravity wells for gravitational slingshot acceleration."
A suicide calculation. In a conduit this narrow, using a gravitational field of sufficient intensity to destroy the armor as a propulsion source — with a tolerance for navigational error of approximately zero.
"Insane —" A pause of perhaps half a second. "— but I'll take it."
Chen Changsheng pulled the thrust control back hard. The armor's attitude thrusters produced several bursts of blue plasma flame. The Stray Dog — which had been in the process of being pulled toward the bottom of a gravity well — rotated its orientation in the same instant and entered the well along the tangential vector instead of the radial one.
The centripetal force generated was sufficient to compress both occupants toward the structural limits of what a human body can maintain consciousness through.
"Now — tangent point — full burst —"
The Planck Engine released its accumulated phase-change energy.
Detonation.
The enormous centrifugal force provided by the gravity well, combined with the engine's instantaneous thrust output, converted the armor into a silver projectile refracting at high speed through the extreme-cold abyss. It cleared one gravity trap. Then another. Each deflection generated a shockwave in the liquid helium sufficient to fracture the conduit's interior wall surface.
Zero's gravity labyrinth was broken by force.
When the armor finally drove through the terminal end of the high-pressure cooling layer and impacted the physical shielding architecture inside Celestial Tower itself, the machine's exterior shell had been abraded down by approximately half. What was exposed beneath was the Heaven's Bone network — silver, pulsing, branching through the armor's structure like the vascular system of something that had decided to survive regardless of the conditions it encountered.
Yi coughed hard and produced blood mixed with anti-shock fluid. She looked ahead.
In the center of a silver forest assembled from thousands of physical baseline instruments, a massive translucent sphere hung without support, luminous, still.
The heart of the City of Perpetual Day. The physical origin point from which Zero had been defining this world for twenty years.
"We're here." Chen Changsheng forced the shattered hatch open. The wrench in his hand had been bent into a curve by the gravity wells. He was holding it anyway.