The north-side wind wheel of Longchime Bell Tower turned once again.
When the news reached the Disaster Affairs Office, Lutia was securing the wheel of the toy car belonging to the child who had found the piece of wood.
She did not use resonance magic.
The wood was uneven in thickness, and the glue had not dried yet. Lorne had her wrap the axle tightly with twine first, then reminded the child not to take it apart until at least tomorrow. The child hugged the repaired wooden car and ran back inside, only to be called back by his mother after two steps to thank them.
Lutia had not yet had time to answer when someone outside the dyehouse called Lorne's name.
A bell-tower duty officer had arrived.
His hat was crooked to one side, the front of his coat was stained with black machine oil, and he was still out of breath as he spoke.
"The lower north-side wind wheel just started up on its own. It wasn't scheduled, and nobody opened the gate."
Lorne immediately closed the work record in his hand.
"Heating-pipe temperature?"
"Normal."
"Main bell mechanism?"
"Unaffected. But the north-side maintenance door is stuck. The workshop crew is taking it apart."
Lutia stood up.
"Which way is the wind going?"
The duty officer glanced at her.
"Don't know. The wind wheel's inside the wall. We normally only watch its speed."
"When did it start?"
"Before the first afternoon time signal. It turned twice, stopped for a while, and just started again."
Lorne asked, "Does the Engineering Office know?"
"They've already sent someone over."
Lutia put on her gloves.
"We'll go too."
Lorne did not move at once.
First he glanced at the bandage still wrapped around her right palm.
"No resonance magic today."
"I'll only sense."
"The range can't exceed the investigation permit."
"All right."
"Don't touch any door without permission."
"All right."
"If you detect a pull underground, say so immediately."
"I was going to say so anyway."
Lorne tucked the clipboard into his satchel.
"You wouldn't have a few days ago."
Lutia did not argue again.
By the time they reached the bell tower, a sizable crowd had already gathered around the north-side entrance.
Longchime Bell Tower was taller than it had looked from a distance. Its dark gray stone walls narrowed as they climbed, with the clock face embedded halfway up and narrow maintenance platforms jutting out around it. Snow had trouble settling on the tower walls; most of it was swept away by the wind above, leaving only lines of white gathered along the windowsills and in the hollows of the stone carvings.
The main entrance faced Bellheart Square. The north-side maintenance entrance was hidden between two attached workshops.
Removed guard panels and a rusted iron frame were piled in front of the door.
Novi sat on a toolbox, her left arm still in a sling, a long, slender wrench in her right hand. The short wooden door in front of her was only half open. Several thin copper shims that had just been removed lay beside the hinges.
Her expression did not improve when she saw Lutia.
"Why is she here too?"
Lorne showed her the investigation order signed by Greta.
"To help identify seasonal resonance echoes."
"Isn't she barred from entering the bell tower?"
"She can't enter alone or approach underground facilities without approval. Today, the Disaster Affairs Office and Engineering Office personnel are present."
Novi glanced over the paper.
"You're only checking the north-side wind wheel?"
"We're checking the north-side wind wheel first."
"Let me make this clear: nobody touches anything inside without permission. Especially her."
Lutia asked, "You're in charge of leading the way now?"
"My master is upstairs inspecting the main bell. I know the lower north side best."
"Your hand still can't lift anything heavy."
"I use my feet to lead the way."
"What if something needs to be dismantled?"
"I call someone else to do it."
"What if they dismantle it incorrectly?"
Novi stared at her.
"Then you still don't get to use wind to tear down the wall."
Lorne pushed open the half-closed wooden door.
"Let's go."
Behind the door was a sloping stone passage leading downward.
An oil lamp was set into the wall at regular intervals, and every flame was blown toward the same side by the current of air. Two narrow iron rails ran along the floor, used to push maintenance tools and bell-wheel parts. Pipes of various thicknesses lined the walls. Some were wrapped in heat-resistant cloth, while others were exposed, their joints stained with black oil.
Lutia sensed that something was wrong as soon as she descended the first stretch of slope.
The thick door kept the wind and snow outside at bay, yet underground it was warmer than the old council hall.
She stopped beside a section of exposed stone wall.
"Are there heating pipes here?"
Novi continued ahead.
"The bell tower can't freeze. Gear oil gets thick when it's too cold, and the bell ropes frost over easily."
"It's snowing outside."
"So the furnace room is burning more often than usual."
Lorne asked, "Where's the heat source for the heating pipes?"
"Under the workshop on the east side."
"The current pipeline map only marks as far as the ground level."
Novi turned back.
"Because you're holding the map used for current maintenance. The levels below have been altered too many times. The old maps and the new ones don't match at all."
"What about that copper conduit at the north gate?"
"I've never seen it on the current map."
"The old map?"
"Find it yourself in a minute."
She pushed open the iron door at the end of the passage.
Behind it was a circular machine room.
A thick shaft ran through the upper and lower levels at the center, surrounded by gears of different sizes. Several sets of wheels were arranged along the walls, their rims fitted with wooden vanes. Most were motionless. Only the set at the very bottom of the north side made a regular scraping sound.
The vanes were not turning quickly.
Every time they completed a rotation, a muffled tremor sounded from inside the wall.
One engineer knelt in front of the wheel to inspect the bearing. Another held up an oil lamp to illuminate the gate in the wall.
"Nothing's jammed in it," the kneeling one said. "The bearing isn't damaged either. The gate is closed, but it's still turning."
Lorne asked, "Where's the wind getting in?"
The engineer pointed behind the wheel.
"Inside the wall."
"What's behind it?"
"According to the current map, a sealed old passage."
Novi crouched beside the wheel and inspected the retaining bolts.
She could only use her right hand. Every time she needed to change the wrench's angle, she first had to set the tool on her knee.
Lutia stood two steps away.
"Do you need help?"
"No."
"I can hold the lamp."
Novi looked up at her.
Lutia added, "Without magic."
Novi glanced at the oil lamp by her feet, which kept swaying from the vibrations.
"Hold it steady. Stay away from the vanes."
Lutia took the lamp.
A row of polished markings ran along the bottom of the wheel. The wooden pointer should have been resting at the far left, but now it jumped to the third mark with every turn of the wind wheel, then slowly slid back.
"The gate is closed, but wind is still coming in," Novi said.
The engineer reached out and felt along the stone seam behind the wheel.
"There's no draft from outside."
Lutia lowered the oil lamp slightly.
"I want to confirm."
Lorne looked at her.
"Only this machine room and the portions behind the wall that already have openings."
"I know."
She did not close her eyes.
The heating pipes, oil lamps, and turning wind wheel inside the machine room all blurred together. Lutia first avoided the most obvious heat. When the wind wheel completed another turn, she caught the very fine pull.
It was the same as at the north gate.
The winter resonance echo in the snow was moving downward along the back of the wall.
But there was another current inside the wall.
Warm, steady, rising from somewhere deeper below.
"There are two directions inside," she said.
Novi stood up.
"What?"
"The winter resonance is moving down. The heat is moving up."
The engineer pointed at the heating pipe beside them.
"The heat comes from the furnace room."
"Not that heat."
Lutia held her left hand half a foot from the wall.
"The heating-pipe heat travels through the metal. The current inside the wall is rising from below."
Lorne asked, "Can you tell how deep it is?"
"No."
Novi tapped the wall once with the handle of her wrench.
"If there's really another passage behind it, why does the current map show only one?"
"You said there was an old map here," Lorne said.
Novi turned toward the other side of the machine room.
Several map tubes and thick books were crammed into a wooden cabinet against the wall. She pulled out the topmost map tube with her right hand, while Lutia supported the other end.
Novi glanced at her but neither let go nor refused her help.
Together, they set the tube on the worktable.
Most of the maps inside had yellowed, their corners stained dark brown by machine oil. Novi searched according to the tower level and year markings, while Lorne set aside the maps whose structures differed from the current layout.
Lutia could not understand most of the engineering symbols.
She could only identify the tower's outer wall, the central thick shaft, and the north-side wind wheel. The older the map, the more lines there were below ground. Some passages had been cut off by later walls. Other areas were simply marked decommissioned.
Novi unfolded a map with no year marked on it.
It showed the lower north side.
Behind the wind wheel was not a short, sealed pipe, but an old passage much wider than the current ventilation duct. Two parallel lines ran through it. Beside one of them, two characters were still legible.
Cold flow.
Only the character for "heat" remained on the other side.
The right half of the map had been torn away along the fold.
"Half of it is missing," Novi said.
Lorne examined the torn edge.
The paper fibers all curled in the same direction. It did not look naturally worn.
"Where did the other half go?"
"I don't know."
Novi pulled a catalog from the bottom of the wooden cabinet.
"This originally had a duplicate. One copy was kept in the workshop, and one was sent to the Engineering Office."
Lorne looked at the fragmentary map.
"What about the Engineering Office's copy?"
"You'll have to ask them."
Lutia followed the cold-flow line north with her eyes.
It pointed directly toward the north gate.
Before the map was torn away, the other heat-flow line bent toward the base of the bell tower.
"Is there a lower maintenance level here?" Lorne asked.
Novi did not answer. She walked around behind the central shaft first.
There was a narrow stairway leading down.
An iron railing blocked the stairwell, with an oil-stained wooden sign hanging on it.
Decommissioned.
Do not enter.
But the lock on the railing was much newer than the sign.
"This lock isn't the original," Novi said.
"Who replaced it?"
"The Engineering Office. People still went down occasionally before. Later they said the structure was unstable and sealed it off."
"Have you been down there?"
"Before it was sealed."
"What's below?"
"Old pipes. A few valve rooms."
Novi raised the oil lamp in front of the railing.
"And a door."
Looking down between the bars, they could see only the first few stone steps. The stairway turned left at the next landing, its end facing a dark door.
The door was not completely hidden in the darkness.
When the oil lamp passed over it, a dull yellow glint of metal appeared first at the center.
It was a set of gears embedded in the door.
The largest gear was about half an arm's width across, meshing on either side with two smaller wheels. The teeth were thick, but their edges had been finished neatly. It was clearly human mechanical construction.
Another kind of carving wound around the doorframe outside the gears.
Lutia took a step forward.
Lorne immediately said, "Stop at the railing."
She stopped.
The oil lamp moved a little lower.
Those carvings were not decoration.
Curving lines overlapped one another, breaking at four points before reconnecting through tiny returning patterns. Lutia had seen similar structures in Springturn Forest.
"That's a boundary seal."
Novi looked at her.
"What?"
"An elven boundary seal."
"What does it do?"
Lutia did not answer immediately.
The distance was too great, and some of the carvings were obscured by oil.
"I can only tell that it's meant to limit an area. I can't tell what it's limiting."
Lorne asked, "Why would human gears be installed in the middle of an elven boundary seal?"
"I don't know."
Novi said, "That door wouldn't open the last time I went down there. The gears were jammed, and I couldn't read the carvings either."
"When was that?"
"Before the seal."
"Is there a record?"
"The workshop's old maintenance log might have one."
Lorne was about to ask another question when the north-side wind wheel suddenly gave a metallic clang.
Everyone turned at once.
The wind wheel stopped for a moment.
The next instant, it turned backward half a rotation.
A low scraping sound came from behind the wall, as if a very heavy metal plate were moving somewhere in the distance.
The temperature in the machine room began to rise.
It was not that the furnace fire had suddenly flared.
Instead, the flames of the oil lamps closest to the wall shortened, and their glass chimneys quickly fogged with moisture. Novi immediately went to the heating-pipe pressure gauge.
"The heating pipes haven't changed."
The engineer also went to check another set of markings.
"The furnace room's heat output is normal."
Lutia stood where she was.
The heat was coming from beneath her feet.
It seeped upward through the stone slabs, rising along the gaps beside the central shaft. She could feel the temperature climbing even through the soles of her boots.
Lorne said, "Everyone away from the wall."
The engineer moved his tools toward the center.
Novi extinguished the two oil lamps nearest the wall.
"This isn't traveling through the current heating pipes."
"It's not fire," Lutia said.
"How do you know?"
"There isn't a resonance echo left by combustion."
She did not crouch or reach out to touch the floor.
The winter pull still sank behind the wall from the north-side wind wheel.
But the heat was rising from somewhere deeper below.
The two currents crossed throughout the machine room without mixing.
At that moment, someone pushed open the iron door.
Sivier stood in the doorway.
He was still wearing his dark blue engineering coat, his wrist wrapped in an abrasion-resistant bandage. Behind him followed an Engineering Office clerk carrying a document case.
He first glanced at the north-side wind wheel, which was turning backward.
Then he saw the fragmentary map on the worktable and the old maintenance stairs lit by the open oil lamp.
"Who authorized you to inspect the sealed level?"
Lorne took out the investigation order signed by Greta.
"The north-side wind wheel started on its own, and its pull is aligned with the copper conduit at the north gate. We're confirming the related structure."
"The investigation order doesn't authorize you to enter a sealed engineering area."
"We haven't crossed the railing."
Sivier walked to the worktable.
His gaze paused briefly on the incomplete map.
"That one was invalidated long ago."
Lorne said, "Invalidated doesn't mean the passage on it doesn't exist."
"A lot of provisional designs were left behind during the tower's original construction. They weren't all completed in the end."
Novi pointed at the north-side wind wheel.
"Then what about this?"
"Return air from the old passage."
"The gate is closed."
"Old gates can't be completely airtight."
Lutia spoke up. "There's seasonal resonance in the wall."
Sivier turned toward her.
"North City is full of your seasonal resonance now."
"The flow here is different."
"How is it different?"
"The winter resonance is being carried downward. There's heat rising from below as well."
Sivier lowered his head and glanced at the fragmentary map.
"An abandoned hydronic heating system."
Lorne asked, "Which system?"
"The bell tower used underground hot water to help keep the machinery warm in its early days. Later, the pipes began leaking, so the system was decommissioned. Only some of the old passages remain."
"Where did the hot water come from?"
"An underground reservoir."
"It's not on the current map."
"Because it was decommissioned."
Lorne pointed behind the railing.
"What about the boundary seal on that door?"
Sivier looked over.
"Elven boundary technology was used in early construction projects."
Lutia said, "That's not ordinary decoration."
"I didn't say it was."
"The gears are in the middle of the boundary seal."
Sivier looked at her.
"Construction three hundred years ago wasn't divided according to current elven and human technology. Seeing two kinds of things on the same door doesn't prove that either still serves a purpose."
Lorne asked, "Why would the copper conduit at the north gate carry snow into the underground levels?"
"That's your assessment from the site."
"The reactions of dry grass and snow are different, and Engineering Office personnel were present."
"Ancient copper conduits may retain seasonal techniques. A decommissioned facility reacting to magic doesn't mean someone is operating it now."
Novi set the wrench on the worktable.
"A decommissioned facility can start a wind wheel on its own?"
"Old pipes can develop pressure differences."
"Can they heat the floor?"
"Underground hot water."
"Can they keep letting in wind with the gate closed?"
Sivier looked at her.
"Apprentice Tann, that's what the Engineering Office is here to investigate."
"Then open the door."
"No."
The machine room fell silent.
Lorne asked, "Why?"
"The lower-level structure hasn't completed its safety inspection."
"How long ago was it sealed?"
"That's not what needs to be discussed right now."
"The anomaly is behind the door right now."
"You haven't proven that."
"That's why we need to investigate."
"An investigation doesn't mean you can send an injured workshop apprentice, a regulated elf, and a disaster records officer with no underground engineering qualifications down there together."
Novi frowned.
"I'm at least more familiar with it than the person behind you who can't even recognize this wind wheel's model."
The Engineering Office clerk carrying the document case raised his head.
"I never said I couldn't recognize it."
"You looked at the nameplate three times."
Lorne did not let the argument continue.
"Where is the Engineering Office's other underground map?"
"We'll check back at the office."
"The old maintenance level's safety report?"
"We'll provide that too."
"The key?"
Sivier paused.
"The sealed level is currently closed to entry."
"That's not where the key is."
"Lorne."
"I want to record who can open this door."
Sivier looked at him.
"The Engineering Office holds it."
Lorne wrote that down in his notebook.
Sivier reached out to take the fragmentary map from the worktable.
Novi pressed down on the map tube first.
She used her right hand.
"This is the workshop's retained copy."
"It concerns a sealed engineering area and must be turned over to the Engineering Office."
"The catalog says it's to be retained at the bell-tower workshop."
Lorne stepped between them.
"Don't take it for now."
Sivier looked at him.
"Reason?"
"The document is directly related to the current anomaly, and it's missing a page. Until the investigation is complete, it stays sealed at the bell tower, with signatures from both the Disaster Affairs Office and the Engineering Office."
Sivier was silent for a moment.
"Fine."
Novi took an empty wooden box from the bottom of the cabinet.
After Lorne and the Engineering Office clerk confirmed the condition of the fragmentary map, they placed it in the box and signed the two overlapping seals.
Lutia did not take part.
She was still watching the door below the railing.
The speed of the north-side wind wheel began to drop.
The heat flow inside the wall changed with it, surging and fading in turns. Nobody had touched the gate, and the heating-pipe pressure remained unchanged.
She said so aloud.
Sivier asked, "Can you determine the cause?"
"No."
"Then record the change. Don't decide in advance that it has an operator."
Lutia looked at him.
"I didn't say who it was."
Lorne had already recorded the wind wheel's markings and the time.
"At least we agree on that much."
Sivier did not answer.
Lorne called over a Disaster Affairs Office clerk by the door and sent him back to the old council hall with a message.
By the time Greta reached the bell tower, the north-side wind wheel had dropped back to around the first mark.
After entering, she first listened to Lorne finish explaining what they had found, then examined the old map, the railing, and the door below.
"Nobody goes down today," she said.
Lutia turned.
Greta continued, "The Engineering Office will provide the sealed level's safety records, key log, and the other map. The bell-tower workshop will provide the old maintenance records. Until all three arrive, this area is sealed."
Sivier said, "If the wind wheel loses control again, the engineers need to be able to get in."
"The current machine room remains open for regular maintenance. The seal applies to below the railing."
"The problem may be down there."
"Which is why the Disaster Affairs Office will be present whenever someone goes in."
Sivier did not object again.
Greta had someone add a second chain lock to the railing, then pasted seals over the original lock and the bars.
Novi stood nearby watching.
"The second section of stairs is missing a rung," she suddenly said.
Lorne looked up.
"The section below?"
"The third step after the turn. It was already broken before."
"Anything else?"
"A pipe sticks out from part of the south wall. It'll hit your shoulder when you walk past. There's a drain in front of the door at the very bottom. It's slippery if you step on it."
Sivier looked at her.
"You've been inside the old level?"
"Before it was sealed."
"How far did you get?"
"To the door."
"Why?"
"I was looking for a wrench that had fallen down."
"That isn't part of the workshop's routine maintenance area."
"That's why I came back up after finding it."
"Did you touch the door?"
"I pushed it. It didn't open."
"The gears?"
"Jammed."
Novi looked down toward the area below the railing.
"I used to think those boundary seals were just carvings left by some unknown generation."
Lutia said, "They're not carvings."
"I know that now."
The two looked at each other for a moment.
Novi looked away first.
Greta noticed that Novi's sling had slipped a little lower on her left arm.
"You still need to go back to the clinic today."
"I was only leading the way."
"And you've finished."
"But the wind wheel—"
"Someone else will take over."
Novi frowned but did not argue again. She picked up her tool bag with her right hand, then stopped at the door.
"If you really need to go down next time, find me first."
Lorne asked, "What about your hand?"
"I use my feet to lead the way."
She left.
Sivier confirmed that the seal would not interfere with maintenance of the current wind wheel, then left with the Engineering Office clerk as well.
The machine room gradually fell quiet.
The north-side wind wheel made two final turns and stopped.
A very low wind still whispered inside the wall.
Greta had the others begin organizing the tools and site records. Lorne stood beside the railing without touching the seals.
"Can you still feel it?"
Lutia nodded.
"Winter?"
"Yes."
She stood outside the railing without crossing the line.
She did not actively extend her senses into the old level either.
Yet the resonance echoes behind the door traveled up the stone stairs on their own.
The clearest was winter.
That part was as familiar as her snow: low temperatures, wind, dormancy, and traces left behind by her own resonance.
There was heat below as well.
Not the heat sent through the heating pipes from the bell tower's furnace room, but a drier, denser seasonal resonance. It was like midsummer pressed into the layers of stone, still not entirely dispersed even behind the door.
A third current was mixed with the sound of water.
Moist. Delicate.
It held the growth resonance that appeared only when a seed was just preparing to split open.
Lutia straightened a little more.
Lorne noticed the movement.
"There's more?"
"Yes."
The fourth was the hardest to distinguish.
It was not as strong as the first three, nor did it move steadily in any one direction. It tightened and loosened in turns, caught between cold and heat, moisture and dormancy.
Lutia listened for a long time.
"Autumn."
Greta looked at her.
"What did you say?"
"There are four seasonal resonance echoes below."
Lorne glanced behind the railing.
"Spring, summer, autumn, and winter?"
"Yes."
"At the same time?"
"At the same time."
Greta asked, "Can you tell what they're doing?"
Lutia shook her head.
"I can only distinguish that they're all there."
"Behind that door?"
"At least, the directions are coming from there."
No one touched the seals again.
A time signal rang from the upper levels of the bell tower.
When the hammer fell, the central shaft shuddered with it, and the railing and the gears on the door trembled faintly in the lamplight.
The door did not open.
Behind it, all four seasonal resonance echoes continued to exist at once.