Sera’s patient was on the other side of a wall that had started bleeding.
The report reached the clinic at dusk. A maintenance worker named Oren was trapped in a lower passage near the regulator return. His companion had escaped and described a fallen frame, a spreading dark fluid, and pale creatures moving through the adjoining tunnel. The companion had also said Oren was breathing when he left him.
“Then we don’t wait for a committee,” Sera said.
Neri looked at the rough sketch. “The frame may still be moving.”
“Then we take someone who can tell us when to stop.”
“I’ll come,” Neri replied.
Iven was already collecting rope. Kesh checked the straps on her repaired shield and took a lantern with a hood that could narrow its beam. Brell sent a worker who knew the lower passage to guide them as far as the damaged stair. Tavin arranged a local cage transfer to bring Oren to the clinic if they found him alive.
Sera carried a medical case and two folded pads of clean cloth. She had no intention of taking a tissue sample until the worker was safe. Iven could see that in the way she packed: bandages and splints on top, sample tubes closed in the lower compartment.
The guide led them beneath the rear saddle. The passage walls here were not smooth. Metal supports stood among pale ridges that curved inward and outward, as if the frame had been fitted around something that moved. A warm draft carried the smell of wet stone and oil.
“The fall is beyond the next turn,” the guide said. “I can’t take you farther. My crew is clearing the upper stair.”
“You’ve done enough,” Neri told him.
He tied a strip of cloth to the rail to mark the route and went back. Iven led the rest around the bend. The fallen frame lay across the passage, its upper end wedged beneath a pipe. Dark fluid seeped from the wall behind it and ran into the drain. On the far side, a hand moved weakly.
“Oren?” Sera called.
“Here.”
His voice was rough but clear. That was better than silence.
The frame had trapped his leg beneath a crossbar. Iven could see his shoulder and one arm. A lamp lay on its side beside him, still burning behind a cracked glass cover.
“Can you move your foot?” Sera asked.
“I think so.”
“Don’t force it. Any trouble breathing?”
“No.”
Neri knelt by the near end of the frame. “The pipe is carrying part of the weight. We can’t lift the frame straight up without pushing the pipe into the wall.”
Iven followed the load. A second support stood beyond Oren, mostly hidden by the fallen frame. If they could pull the crossbar toward the near side while holding the pipe clear, they might free his leg without moving the entire structure.
“I need an anchor,” he said.
Kesh pointed to a sound post beside the passage. Iven tested it with his hand and found it secure. He seated winch draw, plate brace, and ratchet hold. Neri fitted an ordinary rope around the crossbar and tied it to the post through a pulley she had brought from the workshop.
“Small pull,” she said. “I’ll watch the pipe.”
Iven drew the rope toward the post. The crossbar shifted a fraction. Oren cried out.
“Stop,” Sera said.
Iven held the bar with ratchet hold rather than continuing the pull. Sera moved closer and examined the trapped leg through the gap.
“The bar is against his boot. Oren, can you loosen the laces?”
“With one hand?”
“I’ll help.”
She reached through the frame and worked the knot loose. Oren pulled his foot back carefully. The boot remained under the crossbar.
“Again,” Neri said.
Iven pulled another inch. This time Oren’s leg came free. Sera checked for bleeding and found a deep bruise but no obvious break. She and Kesh helped him sit up.
The wall moved.
It was a slow inward pressure, like the movement behind Brell’s mounting but larger. The fallen frame shifted against the pipe. Iven held the ratchet, feeling the force pull at the pattern. It was more than he could sustain for long.
“Out,” Neri said.
They moved Oren toward the turn. The pipe above the frame knocked against its support. Dark fluid spread faster along the wall.
A pale creature came through a low opening behind the frame.
It moved toward the fluid, not the rescuers. Its head pressed against the wall. Then it turned as Kesh’s lantern swept across the passage.
“Keep the light low,” Kesh said.
She narrowed the hood. The creature advanced, its hooked feet clicking on the grating. A second shape appeared behind it.
Iven released the ratchet and reseated piston strike. The frame settled a fraction. Neri watched it, ready to call them back if the pipe shifted.
The first creature lunged. Iven caught its head on a plate brace and struck the exposed leg joint. It recoiled. Kesh moved beside him with her shield, keeping the second creature from reaching Oren.
The second did not attack immediately. It climbed onto the fallen frame and began scraping at the pipe support. Each scrape sent a vibration through the metal.
“It’s going to loosen that bracket,” Neri said.
“Can we move Oren faster?” Iven asked.
“He’s walking as fast as he can.”
Sera and Oren had reached the turn. Kesh backed after them. Iven stayed between the creatures and the retreating group. The first came again, low and fast. He used the narrow passage to his advantage, bracing against the wall and turning the creature’s head into the frame rather than trying to overpower it in open space.
The second creature pulled at the bracket. A bolt dropped. The pipe shifted against the pale surface beneath it.
“Move!” Neri shouted.
Iven followed her to the turn. Behind them, the pipe struck the wall with a heavy knock. The creatures rasped. He did not look back until they reached the stair.
The guide was waiting with two workers and a stretcher. Oren insisted he could walk, then accepted the stretcher when his bruised leg failed on the first step. Sera stayed with him while the workers carried him upward.
Neri stopped at the stair rail and looked back down the passage. “The pipe needs support before they restore pressure.”
“Can we reach the upper valve?” Iven asked.
“Vela can. I’ll tell her what we saw.”
Kesh checked her shield. A fresh scrape crossed the outer layer. “The second one went for the support after the wall moved.”
“Or after the light moved,” Iven said.
“Or because it was already going there.”
Sera heard them and turned. “Write all of it down. Don’t choose one explanation because it’s convenient.”
At the upper landing, Tavin had Cage Seven ready. Oren was loaded with one attendant under Neri’s reduced-load rule. The cage descended toward the clinic while Tavin’s other crew prepared a second stretcher.
Iven went with Neri to Vela’s valve room. The engineer listened to their report and checked a pressure sheet. One regulator cylinder remained active. The damaged return line had been isolated, but the remaining cylinder was carrying a larger share of the load.
“If I reduce this branch,” Vela said, “the pressure goes somewhere else.”
“Where?” Neri asked.
“That’s what I’m trying to find out.”
Vela pointed to a diagram with three branches. One led toward the heat line Brell had closed. Another fed a set of upper pumps. The third disappeared beneath a label marked regulator return. The drawing showed arrows but no description of what the return carried.
Elian arrived with a copy of the ledger entry. He placed it beside the diagram. The mounting numbers matched one branch. The phrase tissue draw appeared beside a maintenance adjustment.
Vela read it twice. “I was told the return carries waste fluid.”
“Maybe it does,” Sera said from the doorway. She had followed after handing Oren to her assistant. “But the fluid beneath the wall contains living fibers.”
Vela looked at her. “You don’t know where it comes from.”
“No. I know what I saw under the lens, and I know a wall is moving against your pipe.”
The engineer sat down. “If the remaining cylinder fails, the branch pressures could change together.”
“How quickly?” Iven asked.
“I don’t know. The system is designed to compensate. I don’t have a diagram of the compensation path.”
Elian put his hand on the ledger copy. “The diagram volume may show it.”
“Then we need it now.”
“I asked. The archive still hasn’t approved access.”
Vela stood. “I’ll ask the control room to request it. They can’t claim the regulator is stable and refuse the diagram used to maintain it.”
Brell entered with a report from the neighboring line. A pipe support there had shifted, and two creatures had been seen near the damage. Her crew had closed the passage and moved the workers out.
“People are saying the creatures caused the turn,” she said.
“Do we know that?” Kesh asked.
“No. But they’re saying it.”
Sera looked at the pressure sheet. “The regulator failed before the movement. The creatures appeared around damaged passages. That doesn’t establish what caused the turn, but the order matters.”
Brell took the sheet and wrote the sequence on the back: pressure warning, cylinder leak, wall movement, sightings. She would show it to the crews without claiming more than the records supported.
Iven returned to the clinic with Sera. Oren lay on a stretcher in the bath hall, his leg splinted. He had begun arguing with an assistant about whether he could go back to work. The assistant was winning.
“He’s alive because we didn’t stop to examine the wall,” Sera said quietly.
“We can examine it later.”
“If it remains accessible.”
“If it doesn’t, Oren is still alive.”
She looked at him, then nodded. “Yes.”
Before leaving the valve room, Vela sent for the worker who had first reported the leak. He traced the route on her diagram, stopping at a junction the drawing placed on the wrong side of a support.
“It’s been moved,” he said. “After the last overhaul.”
“By whom?” Vela asked.
“I don’t know. I came onto the shift afterward.”
Iven checked his description against the marks on the pipe. The worker was right: the branch turned beneath the frame, not above it. Vela corrected her working copy in red and sent the runner back with the location. The change did not explain the pressure, but it gave the next crew a chance of finding the valve in the dark.
That night, the city did not repeat the sharp turn. It moved with a strained, uneven rhythm that made cups tremble on shelves and sent people outside whenever a beam creaked. Neri’s crew inspected supports by lamplight. Tavin’s cage moved fewer people per trip but kept moving. Vale’s kitchen served food until the pot was empty.
Iven sat on the clinic step with his tools beside him. His shoulder ached where the creature had driven him into the pipe frame. Sera had checked it and found no break. She had also ordered him to sleep when the immediate work was done.
“How long is immediate?” he asked.
“Until someone else can take the next shift.”
Kesh sat beside him with her notebook. She had drawn the fallen frame, the fluid, and the creatures’ positions. The drawing did not claim to show what any of it meant.
“I used to think a clear answer would make this easier,” she said.
“Would it?”
“If I knew they were defending the wall, I’d still have to get Oren out. If I knew they were drawn by noise, I’d still have to keep them away from him.”
“Then the answer helps with the next job.”
“Not with the one already done.”
“No.”
A runner came from Vela’s valve room. The control room had requested the diagram volume. The archive would deliver it at first light.
Sera read the note and handed it to Iven. “They finally agree they need it.”
“Will it tell them what to do?”
“I hope so. I don’t know.”
The deck gave a faint, slow movement beneath the step. Iven looked toward the dark line of buildings above the regulator works. The city had bought a few hours. He could not tell whether that was enough.