Soren's map said Floor 171's combat chamber was sixty meters across. The chamber was fifty-two.
Eight meters missing. Not a measurement error, not a cartographic mistake. The walls had migrated inward since the Vanguard's surveyors had mapped the room eighteen months ago. The substrate had physically moved, drawn toward the construction above, the floor's architecture compressing as its material was siphoned upward. The room was shrinking.
Sixteen constructs in a space built for twenty. The combat density was wrong, the constructs packed tighter than the Tower's standard deployment would produce in a sixty-meter chamber. But the Tower hadn't adjusted the construct count to match the reduced space. Sixteen units in fifty-two meters instead of sixty. More bodies per square meter. Less room to maneuver.
The party fought compressed.
Marcus's shield wall was six meters from the rear instead of ten. David's lightning arcs had to tighten their spread to avoid hitting the walls, the substrate close enough that a mis-aimed bolt could discharge into the floor's architecture instead of the target. Kira's movement lanes, the spaces between constructs where the Afterimage threaded her blade work, were narrower. She adapted. Killed three constructs in the first exchange with the close-quarters efficiency that her pre-Tower training had built for exactly this kind of space.
Emma's barriers found less room to deploy. The amber energy panels that she used as deflection surfaces and funnel points needed width to create the angular redirections that channeled constructs into Marcus's kill zone. In the compressed chamber, the angles were steeper, the margins thinner. One barrier missed its optimal placement by thirty centimeters and a construct slipped past the funnel. Maya displaced it before it reached David's position. The displacement was close range, efficient, the kind of instinct-level save that the Void Walker produced when the formation had a gap.
They cleared the floor. Nobody spoke about the room dimensions because everybody had felt them. The walls had been too close. The air had been too warm, the substrate radiating the thermal energy of a material that was actively migrating. Fighting in a room that was feeding itself to the construction above felt different from fighting in a room that was merely trying to kill you. The Tower's combat floors were hostile by design. Floor 171 was hostile and shrinking.
The transition corridor to Floor 172.
"The map's dimensions for the next three floors will be wrong," Noah said. "The migration is accelerating. Each floor closer to 175 has lost more material than the one below it. Floor 172 will be smaller than 171. Floor 173 smaller than 172."
"At what point does the floor become too small to fight in?" Marcus asked.
"I don't know. The migration is progressive. The substrate is leaving slowly, not all at once. But the trend is clear. If we came back in three months, Floor 171 might be forty meters across. Six months, thirty. Eventually the walls close and the floor isn't a floor anymore."
"The Tower is eating itself from the inside," David said. The mage's hand pressed against the corridor wall, the substrate contact maintained. "The construction above is consuming the floors below it. Like a tumor."
"Don't call it a tumor," Maya said. The correction was sharp. Five climbs had taught her that language shaped how people processed threats. "A tumor is mindless growth. This is construction. Something is being built. The construction has a purpose. Call it what it is."
David pulled his hand from the wall. Looked at Maya. Nodded once. He recognized the leader was right and the distinction mattered.
---
Floor 172 was a supply floor.
[FLOOR 172: RESOURCE PROVISION. STANDARD ALLOCATION. INVENTORY AVAILABLE.]
The Vanguard's third cache was in the western alcove, the location matching Soren's coordinates exactly. The substrate container was sealed. Untouched. The Vanguard's red tag intact on the seal's exterior, the identification marking clean and unbroken.
"This one's intact," Marcus said. He reached for the seal.
"Wait." Noah crossed the room. Something in the container's appearance was triggering the developer brain's pattern-matching, the quality-control subroutine that had made him a competent code reviewer before the Tower had made him a Pathfinder. The seal was right. The tag was right. The container's exterior was right. But the right things were too right, too clean, too perfectly matching the Vanguard's standard, as if someone had studied the standard and reproduced it.
He opened the container.
Inside: medical compounds, ration packs, repair tools, barrier stabilization patches. The standard Vanguard supply kit as listed on Soren's manifest. Every item in its documented position. Every label matching the inventory list.
Noah picked up a medical compound canister. Turned it over. Read the label. Standard painkiller, Vanguard formulation, the compound specifications printed on the substrate label in the Vanguard's standard format.
The format was right. The compound name was right.
The batch identifier wasn't on Soren's manifest.
He checked a second canister. Different compound. Same problem. The label's format and naming matched the Vanguard's standard, but the batch identifiers were wrong. Not absent, not blank. Different numbers. Numbers that didn't correspond to any batch on Soren's supply documentation.
"These aren't Soren's supplies," Noah said. "The labels match, the packaging matches, the container placement matches. But the batch numbers are wrong. Someone opened this cache, removed the Vanguard's original supplies, and replaced them with substitutes that look identical."
He set the canister down. Carefully. Because if the contents had been replaced, the replacements might not be what their labels claimed.
"Carr was right," Kira said. From the alcove's edge. Her voice flat. The Afterimage processing the confirmation that the man she'd been hunting had left an accurate warning. "The caches are compromised."
"Not just emptied," Noah said. "Substituted. Someone created convincing replicas of Vanguard supplies and swapped them into the cache. This isn't opportunistic theft. This is a targeted operation. Whoever did this has access to the Vanguard's supply specifications, container formats, and label standards."
"Inside job," Marcus said. The conclusion the evidence supported, and the one Marcus's operational security training reached first. "Or someone close enough to the Vanguard's supply chain to replicate it."
"Can we test the contents?" Maya asked.
"Not without lab equipment. The substitutes could be anything. Inert compounds. Degraded material. Actual poison." Noah stepped back from the container. "We can't use any of it. Carr was right to empty the other two. If he recognized the substitution and removed the contents, he was protecting anyone who found the caches after him."
Emma was standing at the far side of the supply floor, near the eastern wall. She hadn't approached the cache. Her hand was on the wall, a gesture that mirrored David's substrate-contact habit but served a different function. She wasn't listening to the building. She was steadying herself.
Her other hand was pressed against her stomach. Not the gesture of someone who was hurt. The gesture of someone who was feeling something internal that she couldn't stop.
Noah noticed. Filed it. Returned to the cache problem.
"We inform Soren," Maya said. "This affects his infrastructure. All three caches are compromised. His supply chain has a breach."
"Agreed. This we share." Noah looked at the container. The perfect replicas of Vanguard supplies. The batch numbers that told the truth when everything else about the packaging lied. "Soren needs to audit his entire supply network above 160."
The party took nothing from the cache. The waystation's decay-exempt supplies would carry them to 175. Past that, they'd rely on what the floors provided.
---
The signal hit Noah on Floor 172's exit corridor.
Not a gradual detection. Not the faint substrate echo that he'd caught on Floor 155 when the other Pathfinder and he had first sensed each other. This was a burst. A Path Sight activation punching through the substrate like a distress flare, the cognitive-frequency signal broadcasting at a volume that made Noah flinch.
The signal was wrong.
He'd felt his own Path Sight's frequency. He'd felt the Shadow's frequency in the labyrinth inscription. Both were clean, organized, the golden-line architecture operating within its designed parameters. This signal was fractured. The cognitive frequency stuttering, the signal dropping out and surging back in irregular pulses, the pattern of a system that was losing coherence. Like code executing with corrupted memory addresses, producing output that was partially functional and partially garbage.
The Pathfinder above them was activating. And their Path Sight was breaking.
"Noah." Maya had seen him stop. She could read the physical indicators of someone receiving information through a channel she couldn't access.
"The other Pathfinder," he said. "They're activating. Close. One floor above us." He pressed his hand against the corridor wall. The substrate transmitted the signal's directional component. Above. Directly above. Floor 173. "The signal is damaged. Their cognitive architecture is degrading. Path Sight is burning out."
"Burning out?" David said. The mage who understood what the Tower's systems did to the people who used them.
"The frequency is unstable. It's like watching a processor melt down. The activation is producing output but the output is corrupted. The signal clarity is maybe thirty percent of what mine is." Noah kept his hand on the wall. The other Pathfinder's signal was fading. Not slowly. In stuttered drops, the activation holding for a second, cutting out, holding again. "They're trying to maintain it and they can't."
The signal cut. Three seconds of activation. Then gone.
"One floor up," Noah said. "Floor 173. They activated, held for three seconds, and lost it."
"Why three seconds?" Marcus asked. The marine assessing the tactical implication.
"Because that's all they have left. Their Path Sight is failing. Each activation is shorter than the last. The forty-seven activations the Vanguard logged above Floor 165 over three months, the Shadow said they were running. Running and activating." He pulled his hand from the wall. "They're activating because they need the routes. They can't navigate these floors without Path Sight. And their Path Sight is dying."
"They're on 173 right now," Kira said. The Afterimage's spatial awareness calculating the proximity. "We're on 172. One floor between us."
"If they can't navigate, they can't clear the floors efficiently," Maya said. The leader's assessment running the scenario. "A Pathfinder with failing Path Sight in floors that are structurally unstable, with real-time adaptation and architecture that's migrating. They're trapped in the worst possible section of the Tower with their primary ability degrading."
"They're not just running from what's above 175," Noah said. "They're running from their own failure state. Path Sight is eating their ability faster than it's eating mine, and they don't have a party to compensate."
"Solo Pathfinder," David said. Quiet.
"Solo Pathfinder with no party and no ability."
The transition corridor's thirty-second window was closing. Floor 173's portal was ahead. The other Pathfinder was on Floor 173. One portal away from contact.
Emma moved to Noah's side. Not the casual proximity of a sibling walking together. The specific, deliberate approach of someone who had been processing information through a channel the party didn't know about and had arrived at a conclusion she needed to share before the next floor opened.
Her hand closed on his arm. The grip was tight. Tighter than the pressure-communication she normally used. The grip of someone holding on to something to keep herself steady.
"I need to tell you something," she said. The fast cadence. But not excitement-fast or nervous-fast. Urgency-fast. The blade dancer who processed under pressure and was producing output at speed because the situation demanded it. "About the deal. About how it works with Pathfinders."
"Now?"
"Now. Before we go through that portal." Her eyes were on the portal ahead. The amber energy of her barriers was flickering at her free hand, the involuntary response she produced when her deal mechanism was active and running. "The mechanism installed by the Tower on Floor 12. It transmits observations about climbers. But it does something different when a Pathfinder is nearby. Something I didn't understand until right now."
"What does it do?"
"It activates a secondary process. A collection protocol. The deal doesn't just observe Pathfinders." She looked at him. Her eyes had the wide focus of someone watching something happen inside their own body that they couldn't control. "The Tower's deal. When a Pathfinder is dying, the deal mechanism activates differently. It's happening right now. The Pathfinder above us isn't just running. The Tower is trying to collect."
