The evacuation from Harbor Exchange did not look like panic at first, because Mara had trained her people too well for that kind of easy disaster. Families packed blankets, water tins, tools, medicine, and whatever food could be carried without slowing the line, while guards moved through the corridor checking shutters and counting people under their breath. Arthur stood near the blocked shaft with Nora and Sam, watching a whole settlement fold itself into bags in less than five minutes, and the speed of it made him feel worse than if everyone had screamed.
Nobody blamed him out loud, which was somehow less comforting than being yelled at. A few people looked at him as they passed, then quickly looked away, as if staring too long might wake whatever was sleeping under his shoes. Arthur kept his eyes forward and tried not to think about the fact that these people were leaving their home because danger had followed him into it like a stray dog with too many teeth.
Mara moved at the front of the group with a lantern in one hand and her radio in the other, giving orders in a low voice that carried just far enough. The north passage had been hidden behind a locked maintenance gate at the end of the upper retail level, where old signs warned STAFF ONLY and AUTHORIZED PERSONNEL BEYOND THIS POINT, which felt almost funny considering the world had moved beyond employee policy. Sam broke the lock with his crowbar, then stepped aside while Mara pulled the gate open and revealed a long concrete corridor sloping into darkness.
Cold air moved out of the passage the moment the gate opened, carrying a smell like dust, rainwater, rust, and something dry that Arthur could not place. The tunnel beyond looked older than the station itself, with thick pipes running along the ceiling and faded yellow lines painted along the floor to guide maintenance crews that were no longer coming. Nora adjusted the pack on her shoulder, glanced down at Arthur's bad ankle, and gave him the look of someone deciding how much help he would accept before becoming annoying.
"I can walk," Arthur said before she asked.
"I know," Nora said, which was worse because it sounded like she had already planned to ignore him if necessary.
The first group entered the north passage in a careful line, with guards at the front, families in the middle, and the injured carried between people who were too tired to complain. Mara sent Sam near the rear with two other guards, then pointed Arthur and Nora toward the center of the line. Arthur understood the logic immediately, because if something came from behind, his shadow might wake up, and if something came from ahead, at least he was surrounded by people who knew what to do before dying became the plan.
The gate closed behind them with a heavy metallic scrape, cutting off the last clear view of Harbor Exchange. Arthur looked back through the bars for one second and saw lanterns swinging over the empty corridor they had just left, the blocked shaft still pressed under a metal cabinet, and the old station beyond it trembling in silence. It did not look like a home now, only a place holding its breath before being swallowed.
Then Mara locked the gate.
The sound echoed down the tunnel.
Arthur hated how final it felt.
They moved north in silence, and the tunnel slowly swallowed every familiar sound from the settlement behind them. The floor sloped downward at first, then leveled out into a long service corridor where old cables hung from cracked brackets and water dripped steadily through the ceiling. The lanterns threw soft circles of light around the moving line, but everything outside those circles stayed thick and black, as if the dark had weight.
Arthur walked beside Nora, keeping one hand against the wall whenever his ankle slipped on wet patches. The pain had settled into a steady throb that rose with every step, but he preferred it to thinking too much. Pain was simple, honest, and not currently pretending to be a receptionist.
After several minutes, Arthur noticed the first marks on the wall.
They were not warning signs like the black X symbols in the service tunnels below. These were names, dates, arrows, and short messages scratched into the concrete by people who had passed through before. Some were practical, like WATER LEFT AFTER 200 STEPS, while others were small and human in ways that hurt more than they should have.
Mara paused beside one message and lifted her lantern, Arthur read it without meaning to.
IF YOU HEAR YOUR MOTHER, KEEP WALKING.
Nobody explained it.
Nobody needed to.
The line moved again, slower now, because the tunnel narrowed where old support beams had shifted. People ducked under pipes, stepped over broken panels, and passed children from one set of arms to another whenever the floor became too uneven. Arthur saw Mara helping an older woman over a cracked section of concrete while still watching the dark ahead, and he wondered how many times she had done this before.
Sam drifted closer from the rear after a while, his crowbar resting against one shoulder. He looked tired enough to fall asleep standing, but his eyes kept moving across the walls and ceiling. Arthur had seen that look on Nora too, and he was starting to understand it as the expression of people who had survived by never letting the world become background.
"Are the north tunnels always this quiet?" Arthur asked.
Sam glanced at Nora before answering.
"No," he said.
Arthur waited for more. Sam did not add more.
Nora sighed softly. "The north tunnels used to connect to three shelters, two water stores, and an old train depot, but people stopped using them after things started copying voices down here."
Arthur looked at the dark ahead. "By things, you mean the false ones."
"Mostly," Nora said, which was not a word Arthur enjoyed.
The tunnel curved left, and the air grew drier. The damp smell faded into something older, like dust and sun-baked concrete, even though they were underground. Arthur noticed the pipes overhead had ended, replaced by square ventilation ducts that had collapsed in places and left jagged holes above them. A sound came from one of those holes. Everyone stopped.
It was small, almost too small to notice, a dry scrape inside the ductwork above the line. Mara lifted one fist, and the entire group froze under the lantern light. Arthur stood with one foot halfway raised, barely breathing, while the scrape moved overhead from one vent opening to the next. A child whimpered near the center of the group. The scrape stopped immediately. Arthur felt Nora stiffen beside him.
Mara turned slowly and pressed one finger to her lips, though nobody needed the reminder now. The child's mother held him close, covering his mouth gently while tears ran down her face. Arthur stared at the vent above them and saw nothing except black metal and dust.
Then something whispered from inside the duct. "Hungry." The word was soft, almost curious. Arthur felt his skin crawl. No one moved.
The whisper came again, slightly farther ahead this time. "Hungry."
Mara lowered her hand slowly and pointed two guards toward the front of the line. They moved without speaking, lifting long metal rods with hooked ends. Nora pulled Arthur back by the sleeve, guiding him closer to the wall.
"What is it?" Arthur whispered.
"Thinmouth," Nora said, barely moving her lips.
Arthur looked at the duct. "That name is extremely direct."
"It fits."
The scrape moved ahead of them, then behind them, then above them again, much too fast for anything crawling normally through a metal duct. The line stayed frozen while the thing circled overhead, whispering the same word in a soft, dry voice that made Arthur's throat tighten. He looked down at his shadow, but it lay still beneath the lantern light, too faint to offer even false comfort.
Mara waited until the scraping moved farther ahead. Then she signaled the line forward. They moved slowly beneath the vents, each step placed as carefully as if the floor were glass. Arthur kept his mouth shut and his breathing shallow, because apparently being loud underground was an excellent way to join the menu. The duct above him flexed once as something passed over his head.
A drop of something clear fell onto his sleeve. Arthur looked at it. Nora saw him looking and shook her head slightly. Do not react. Arthur did not react, which felt like one of the greatest achievements of his life. They almost made it past the vents before the accident happened. One of the younger guards near the rear slipped on a loose pipe casing, and the metal rolled under his boot with a sharp clatter that filled the tunnel. Everyone froze, but the sound had already done its job. The duct above the rear group buckled downward with a violent snap, and something pale and narrow dropped halfway through the opening.
It had no eyes that Arthur could see, only a long slit of a mouth stretching across a face too thin for its skull. Its arms were jointed tightly against its body, and its fingers hooked into the vent edges as it lowered itself toward the guard who had slipped. The mouth opened wider, showing rows of needle-like teeth that clicked softly together.
Mara threw her lantern at it.
The glass burst against the duct, splashing fire across the creature's face. It recoiled with a dry shriek and pulled itself back into the vent, but the whole ceiling came alive with scraping afterward. More whispers moved through the ducts, overlapping now, all saying the same word.
"Hungry."
"Hungry."
"Hungry."
Mara shouted, "Move!"
The line broke into controlled motion, not a stampede, but close enough that Arthur felt people pressing behind him. Nora grabbed his arm and pulled him forward as the vents above them bent under moving bodies. Sam shoved an old rolling cart under one opening just as a Thinmouth dropped through, pinning it against the wall long enough for two guards to drag a child past. Arthur limped faster than he thought possible.
The tunnel ahead widened into an old maintenance storage room with concrete pillars and broken cages where tools had once been kept. Mara waved people through the room toward another corridor on the far side. Thinmouths moved overhead in the ducts, their bodies scraping metal so hard the ceiling rained dust. One dropped near the center of the room.
A guard drove a hooked rod into its shoulder and pinned it long enough for Mara to slam a metal shutter down from an old storage rack. The creature twisted under the shutter, mouth opening and closing with dry clicks. Arthur saw its head turn toward him even though it had no eyes. He looked away and kept moving. A second Thinmouth dropped in front of Nora. Arthur reacted without thinking.
He swung the bent pipe into its side, not hard enough to kill it and probably not hard enough to hurt it properly, but hard enough to knock it off balance. Nora caught the opening and drove her knife into the duct strap above it, bringing a loose section of metal down on the creature's back. The thing shrieked and folded under the weight as Nora shoved Arthur forward.
"That was useful," she said.
Arthur nearly tripped over a broken cage door. "I prefer useful from farther away."
They reached the far corridor just as Mara counted the last group through. Sam came last, backing into the passage with his crowbar raised while two Thinmouths crawled across the storage room ceiling behind him. Mara grabbed a lever beside the corridor entrance and pulled down with both hands. An old fire door dropped from the ceiling. It jammed halfway.
Arthur saw the problem at once. A bent guide rail had caught the door on one side, leaving enough space for a Thinmouth to crawl under if it reached them. He limped forward, jammed his pipe into the rail, and twisted. The door dropped another foot.
"Again," Mara said.
Arthur twisted harder. The rail snapped straight enough for the door to slam the rest of the way down. A Thinmouth struck the other side almost immediately, and the metal dented inward with a sound like a fist hitting an oil drum. The whole group stood there, listening as more bodies hit the door from behind. The door held, for now. Mara looked at Arthur.
"That was useful too."
Arthur leaned against the wall, breathing hard. "Please stop sounding surprised."
Nobody laughed for long. The north corridor beyond the fire door stretched into older tunnels where the concrete had cracked in long diagonal lines. The air was drier here, and the ceiling sat lower, forcing taller survivors to duck in places. Arthur noticed there were fewer markings on these walls, which either meant fewer people came this way or fewer people lived long enough to leave advice.
Both options were horrible. They walked for another ten minutes before Mara allowed the line to slow. The children were moved toward the center again. The injured were checked quickly under lantern light. Someone passed water along the line in a dented bottle, and when it reached Arthur, he drank without asking whether it was clean. Standards had changed.
Nora stood beside him while Sam checked the corridor behind them. Her face looked calm from a distance, but Arthur saw the tension in her fingers as she wiped her knife on her sleeve. She was tired too, and that scared him more than he expected.
"How far do these tunnels go?" Arthur asked.
"All the way to North Yard if the route is open," Nora said.
"And if it is not open?"
"Then we find out what blocked it."
Arthur looked at her. "You have a gift for making answers worse."
Nora almost smiled. The tunnel ahead ended at a wide metal door with faded letters painted across it.
NORTH MUNICIPAL MAINTENANCE DEPOT
The door stood slightly open. Mara stopped the line fifty feet away. Arthur stared at the gap. A dull blue light shone through it, weak but steady, unlike the lanterns and emergency lights they had been relying on all night. There was no sound from inside, not even dripping water. Mara lifted her radio and tried three short clicks. No answer came back.
Sam stepped closer to the door, but Nora caught his shoulder. "Wait."
Arthur looked at the floor near the entrance. Dust covered most of it, but the dust had been disturbed by tracks. Not footprints exactly. Long drag marks crossed the ground and vanished through the gap in the door. Something had gone inside recently, or something inside had dragged something else in.
Mara saw him looking. "What do you see?"
Arthur pointed. "Those marks do not look old."
Mara crouched, touched the dust, and rubbed it between two fingers. Her expression tightened. She looked at Nora, and whatever passed between them made Sam raise his crowbar. Arthur looked at the blue light beyond the door. For the first time in a while, his shadow moved without being attacked first. It stretched forward, barely an inch, then pulled back as if warning him away.
Arthur swallowed. "Nora."
"I saw it." Mara stood slowly.
The door creaked open another inch by itself. The blue light brightened. A voice came from inside the depot, calm and clear and nothing like the false ones.
"Harbor survivors," it said. "You are late."
Everyone in the tunnel froze.
Mara stepped forward, lantern raised. "Identify yourself."
The voice answered after a short pause.
"My name is Dr. Voss," it said. "And if Arthur Pringle is with you, bring him in before the things behind you catch up." Arthur felt every survivor turn toward him again. He closed his eyes for one second. Of course," he said quietly. "Why would this get less personal now?"