The man who had been carried out of filter bank nine was angry enough to stand when Iven and Sera found him, which was an improvement over being carried anywhere. He got halfway out of his chair before his legs decided they had not agreed to it.
“I can walk,” he said, clutching the edge of a workbench.
“Then sit down and demonstrate it later,” Sera told him.
He sat. A woman in a stained apron adjusted the folded blanket around his shoulders with a patience that suggested she had already had this argument. The man had a raw scrape across his forehead and a white band of skin where a mask had covered his mouth.
“What were you breathing?” Sera asked.
“Dust. I think.”
“What did it smell like?”
“Hot pennies.”
“Did your lamp change color?”
“I wasn’t looking at the lamp.”
“Did it go out?”
“No.”
Sera accepted that much. She asked him to follow her finger with his eyes, then pressed a cup of water into his hand. Iven waited while the man drank. The workshop around them had been cleared in a hurry: a half-built filter frame leaned against the wall, and a row of baskets lay overturned near the door. Through the open loading hatch he could see the narrow walkway leading toward the bank.
The man wiped his mouth. “I’m Oris. The other one was Pellan. He went to tell the board.”
“Brin said Maret fell through the floor,” Iven said.
“Not the whole floor. A panel tipped. It had been loose for a week, but the board wouldn’t close the bank just because of a loose panel.”
“Why was she there?”
“Because the inner pressure gauge went wrong. She wanted the number before they changed the screens.” Oris stared into the cup. “She told me to wait. I told her I wasn’t paid to watch her do my job.”
“Then what?”
“A thing came up under her. Pushed the panel sideways. I grabbed her sleeve, but it tore.”
He showed them a strip of gray cloth, caught on a nail beside the bench. The edge was jagged. Iven took it down and folded it into his pocket with Lill’s scarf.
“You said it came up,” Sera said. “Did it attack you?”
“It had legs and it was inside the platform. I didn’t stop to ask what it wanted.”
“What did it do after the panel fell?”
Oris frowned. “Turned around. Went back underneath. Pellan had a lamp on it for a moment.”
“Toward the drill?” Iven asked.
Oris looked up sharply. “How did you know about that?”
“Someone told us there was drilling.”
“There was. They stopped when the air got bad.” His fingers tightened on the cup. “Are you going after her or collecting a story?”
Sera opened her case and handed him a small packet of folded cloth. “Breathe through this if the dust starts up again. Stay near the hatch. If Maret comes out another way, keep her here until I see her.”
The woman beside him offered them a lamp and a length of rope. Iven held up his own coil, then accepted the lamp. One rope was useful. Two meant he could be wrong about one of them.
At the walkway’s end stood the first grate, a tall frame of slotted iron designed to keep large debris out of the bank. The second lay beyond it, lower and set across a narrow opening. Iven could see fresh pale dust gathered around its hinges. Beyond that, the passage bent out of sight.
Sera put on the repaired hood. Iven adjusted his own mask, checked the seal along both cheeks, and felt for the winch pattern in his arm. He could hold two functions ready. The filter was the sensible choice for one. The winch was the other; if he needed the bell, he would have to make room for it.
He touched Sera’s shoulder and pointed at his ear, then at her face. “If I can’t hear you, make me look.”
She raised her hand, palm out, and pointed two fingers toward her eyes. He copied her. It was a small agreement, but he felt better after making it.
They went in.
The first section was broad enough for two people to walk side by side. A pipe as thick as Iven’s chest ran along the ceiling, its joints bound with metal collars. Warmth came through his coat from the left wall. The right side held a row of inspection doors with numbers stenciled above them. Nine was at the far end, where the floor had changed color under a drift of dust.
The air grew close. Iven’s mask let him breathe, but each breath took more effort than it had in Sera’s clinic. He tried his small filter effect around the intake and felt some of the grit stop catching against the cloth. The improvement was real but modest. His arm warmed; he let the effect go after a few breaths. There was no sense spending it while the mask worked.
Sera crouched beside the second grate. A shallow scratch crossed one bar. Another marked the floor behind it, cut through the dust into the dark metal underneath. Iven held the lamp low. The scratches continued toward the bend, spaced irregularly.
“Too wide for a boot,” he said.
Sera nodded. She examined the hinge, then pointed to a wedge driven beneath the frame. It had been pushed in from the far side, preventing the grate from swinging fully shut.
“Someone left themselves a way out,” Iven said.
He eased the grate open. It scraped along the floor. The sound made him wince, though he heard it only as a dull drag.
Beyond the bend, the passage opened into a chamber crossed by narrow platforms. A filter housing rose through the middle like a squat tower. Its upper half was a metal cylinder; below, the supports disappeared into a dark mass that moved slowly enough Iven first mistook it for a shift in the lamplight.
Not machinery, then. Or not only machinery.
The loose panel Oris had described hung at an angle on the far side of the housing. A hand lamp burned on the platform beside it, its glass cracked. Underneath, somewhere in the dark, metal tapped three times.
Iven set his lamp on the floor and struck the grate with his spanner: three knocks, a pause, then two.
The reply came after a moment. Three knocks.
Sera squeezed his shoulder. She had heard it too.
Iven walked out on the nearest platform. It gave under his weight and rose again with a slow, uneven motion. The railing had been repaired in several places; one of the patches was a strip of polished brass that looked almost cheerful among the rust.
He stopped where he could see beneath the tilted panel. A pale shape occupied the space below it, wedged between a pipe and the dark moving surface. For an instant he thought it was another creature. Then a hand lifted from the shape, fingers spread against the light.
“Maret?”
“Yes.” Her voice was weak but clear enough for him to hear through the mask. “Please tell me you brought a ladder.”
“Better. A doctor.”
“Can the doctor climb?”
“Better than you can, apparently,” Sera called.
Maret made a short sound that might have been a laugh. “Then we’re saved.”
The panel had trapped her left leg below the knee. She could move her foot, but the angle prevented her from pulling free. A length of pipe had bent under the panel’s edge and was holding some of its weight. Without it, Iven thought, her leg would already have been crushed.
He lay flat on the platform and reached down. His fingertips missed the panel by the length of his hand.
“I’m going to lift it,” he said. “When I tell you, pull toward the pipe. Not toward me. There’s a bracket under you, and I don’t want you caught on it.”
“There’s a bracket?”
“Now that you’ve mentioned it, I think it may be a chair.”
“You’re a comfort.”
He looped the rope around a support post and fed the end down through a gap. Maret caught it with difficulty and passed it around the panel’s narrow end. She had to stop twice to breathe. Her mask hung loose at her throat, one strap torn.
“Air’s worse below,” she said. “The dust comes and goes.”
Sera had been studying the chamber. She pointed to the upper cylinder. “That housing is still running. When the pressure changes, it pulls air through the break.”
“Can we stop it?” Iven asked.
“Maybe. I don’t know what else it’s feeding.”
He didn’t like the answer, but he liked it better than a confident guess. He braced his boots against the post and pulled the rope until it was taut. Then he drew on the winch pattern. A steady tug answered through his left arm. The rope tightened farther, and the panel began to rise.
Maret pulled her leg. It moved an inch and stopped.
“Bracket,” she said through clenched teeth.
“I knew it wasn’t a chair.”
Sera lay beside him and reached down with a narrow instrument. She felt along the edge, then made a sharp motion with her wrist. A metal clip dropped into the dark.
“Now.”
Maret dragged herself sideways. Iven held the pull until she had cleared the panel, then eased it down against the bent pipe. The effort left his forearm hot and his stomach hollow. He rolled onto his back, breathing hard through the mask.
Sera helped Maret get a rope around her chest. Together they hauled her up, inch by inch, until she could grasp the platform rail. Iven caught her under the arms and pulled. She landed against him with enough force to drive his shoulder into the floor.
“Sorry,” she said.
“Don’t be. I was looking for somewhere uncomfortable to sit.”
Sera checked Maret’s leg. The skin was bruised and swollen, but there was no blood on the stocking and the foot was warm. “Can you put any weight on it?”
Maret tried and shook her head. “I can hop.”
“You can lean on us.”
They had reached the end of the platform when the chamber trembled. The filter housing gave a low groan. Dust fell from the upper pipe, and the warm surface beneath the supports contracted in a slow ripple.
Something struck the underside of the platform.
Iven swung the lamp down. A pale armored head appeared between two supports. The creature’s plates overlapped like badly fitted tiles. It had several limbs, more than he could count before it moved again, and a narrow mouth that opened against the pipe rather than toward them.
Maret swore. “That’s it.”
The creature pulled at the bent pipe. Metal shrieked. It ignored the lamp until Iven shifted it, then turned toward the movement. He saw no eyes, only a row of dark pits along the side of its head.
“Back,” Sera said.
Maret could not go quickly. Iven put the rope into Sera’s hands and stepped between them and the creature. His winch was still seated. The bell was not. He needed a free hand and a few seconds to change it, and the creature was already climbing onto the platform.
He threw his lamp past it.
The lamp struck the filter housing, broke, and spilled flame across the metal plate. The creature recoiled from the sudden light. Iven seized the nearest railing with his right hand and pulled with the winch through his left. The railing did not move; he did. He slid forward, boots scraping, and drove his shoulder into the creature’s side.
It was heavier than it looked. They both struck the edge of the platform. One of its limbs caught his coat. He hit it with the spanner, once against the joint, and felt the limb loosen. He pulled free and scrambled backward.
Sera had Maret at the grate. “Iven!”
The creature followed him two paces, then stopped. Its head turned toward the bent pipe again. It climbed down into the dark and struck the damaged metal repeatedly, each blow making the platform jump.
Iven did not wait to learn whether it would change its mind.
He closed the second grate behind them and drove the wedge into the near side. It would not hold forever. It only needed to hold long enough for the three of them to reach the first grate.
Outside, Oris rose from his chair without help. Lill was beside him. She saw Maret and put both hands over her mouth. Maret, leaning between Sera and Iven, looked up and managed a tired grin.
“I missed dinner,” she said.
Lill crossed the distance in three steps. She did not embrace Maret immediately; she looked at the injured leg, found a place to put her hands without hurting it, and then held her carefully. Iven stepped away to give them room.
Oris stared at the torn sleeve in Iven’s hand. “She had that on when she fell.”
“She can have it back,” Iven said. “It’ll need stitching.”
Oris took it, then followed the others toward a waiting cart. He did not thank Iven. He looked as if he was saving the words for Maret, and Iven could not object to that.
Sera stayed behind. She took a little packet from her case and held it beneath Iven’s left hand. A few pale grains had collected in the fold of his glove. He shook them into the cloth.
“You think it came from the creature?” he asked.
“Or the pipe. Or the wall. I’ll look.” She tied the packet shut. “You were nearly out of reach when you pulled yourself forward.”
“It worked.”
“It did.” She looked at his arm. “How much do you have left?”
He considered the tired, warm feeling beneath the skin. “Not enough to enjoy a second one of those.”
“Good answer.”
The last of the dust drifted out through the loading hatch. Inside the bank, the blows against the pipe had stopped. That did not mean the creature had gone, or that the pipe was safe, or that Maret would walk tomorrow. It meant they had time to close the chamber properly and ask what had put the thing there.
Iven looked down at the burned lamp in his hand. Then he looked again. He had thrown the workshop’s lamp, not his own. The woman who had lent it to him was standing beside the workbench, watching the cart leave.
He went to tell her what had happened.