Finn chose to move before the morning rush.
That was probably the smartest hour for it. Orario had already started waking up, so a small group passing through Daedalus Street would not draw much attention, but the louder adventurers had not flooded the roads yet.
A few shopkeepers were lifting shutters, Guild workers were dragging carts through side streets, and the first parties heading toward Babel made enough noise that nobody cared too much about one more group walking with covered equipment.
Rayleigh still thought any plan that dragged him out before breakfast deserved criticism!
The temporary treatment point had been set up in an old Guild storage room connected to one of the sealed service passages.
Someone had cleared it in a hurry.
The floor still showed clean streaks where crates had been dragged away, and the air smelled of dust, lamp oil, and the sharp bite of medical alcohol.
Airmid had taken one look at the room and quietly rearranged half of it, turning a neglected storage space into something that could actually receive wounded adventurers without embarrassing the word "clinic."
Potions, bandages, sedatives, Mind-restoring draughts, sealed cloth, and a few tools Rayleigh recognized only because she had explained them before were lined up neatly along a table.
A folding screen stood near the wall in case anyone needed privacy, and a second table had been kept clear for contaminated equipment.
The room looked plain, but the setup was thoughtful.
Airmid had prepared for panic, bleeding, strange residue, and stubborn adventurers who would insist they were fine while actively falling over.
Shakti and two members of Ganesha Familia handled the outer door.
That was another good choice. Shakti did not crowd the treatment area, and her people kept their voices low.
No one flared magic, no one played at intimidation, and no weapon knocked loudly against the stone.
After seeing Lott nearly lose control from a brush of spiritual pressure, Rayleigh was happy to have guards who understood that "secure the room" did not mean "make the wounded feel cornered."
Welf arrived with Tsubaki not long after, carrying a cloth-wrapped box against his chest.
He looked awful in the very specific way of someone who had slept badly and hated being told to stay behind.
His hair was messier than usual, his mouth was set in a hard line, and he walked like he was daring someone to call him useless.
Tsubaki, naturally, looked like she had been enjoying his mood all morning.
Welf put the box down on Rayleigh's table. "The grooves are deeper this time. Tsubaki checked the throwing ones, and the fixed markers should bite into stone properly. If they fail because someone smashes them in wrong, that's not on me."
Gareth, who was adjusting the strap on his gauntlet nearby, laughed from deep in his chest.
"A proper tool should survive a little rough handling, lad."
Welf's face twitched, and Rayleigh could already see the argument lining itself up, so he opened the box before the boy took the bait.
The markers looked like dark metal spikes, plain enough at first glance.
Each one had a carved channel meant to hold a faint line of Rayleigh's spiritual power, something he could sense from a distance even if the passage twisted or the light failed.
They were not elegant, but they had the solid feel of work made by hands that cared more about function than praise.
Rayleigh picked one up and let a thin pulse run through it.
The groove held.
He tested a second, then a third, before setting them back into the cloth. "Good. These will do."
Welf tried to look like the result had never been in doubt. "Of course they will. I wasn't carving decorations."
Tsubaki hooked an arm around his neck and dragged him down with a grin.
"Hear that? The brat's already proud. Give him another month and he'll start glaring at customers who touch his blades wrong."
"I already do that!"
"See? Natural talent."
Airmid looked up from her supplies, her voice calm enough to make the teasing land softer.
"If he is going to glare at people all morning, he should eat first. Tired hands make poor cuts."
Welf glare at her. "I'm fine!"
"You are tired, upset, and trying very hard to look fine. That is different." Airmid reached into one of the supply baskets and took out a small wrapped biscuit.
"Eat something before your pride becomes a safety issue."
Tsubaki burst out laughing.
Welf took the biscuit with the expression of a man being forced to accept public defeat in front of every god in Heaven.
"Everyone here is unbearable!"
Rayleigh closed the marker box and patted it once. "That means you fit in."
Finn arrived before Welf could answer, Riveria and Gareth falling naturally into place behind him.
The moment Finn entered, the room's scattered energy sharpened.
He did not raise his voice or demand attention. He only looked over the equipment, the guards, the medical setup, and the people present, and somehow everyone understood that the operation had properly begun.
He unfolded the map on the table.
"We enter through the old maintenance passage and follow the Guild route until the first suspected shift point," Finn said. "Rayleigh's markers will help us confirm whether the route behind us remains stable. We move slowly, avoid unnecessary contact with the walls, and return once we confirm the hidden passage. Rescue takes priority if we find living captives within reach, but we do not follow voices or signs deeper without verification."
Alise stood with her arms folded, jaw tight. "I understand the rule. I'm not planning to sprint after every sound in the dark, but if someone is really trapped in there, I won't walk away because the mission title says 'probe.'"
Finn did not look irritated.
He had probably expected that exact response from her. "That is why I want you on the team. You will not ignore someone in need, and I do not want an investigation team that can. I only need everyone to remember that Evilus has used compassion as bait before."
Alise breathed out through her nose, clearly hating how reasonable that was.
"Fine. We check first. Then we move."
Kaguya stood beside her, elegant and relaxed in a way that made the room feel more dangerous rather than less.
"If a wall starts crying for help, I will assume it is guilty until proven otherwise."
Alise turned her head. "Please don't interrogate a wall while someone is actually dying behind it."
"Then the victim should make an effort to sound less like suspicious stone."
Ryuu touched the hilt of Haineko, her voice quiet but practical.
"If there is air movement, dust, ash, or a real person breathing behind the wall, I may be able to tell before we open anything. I will check first."
That helped.
Alise's shoulders loosened a little, not because the rule became easier, but because Ryuu had given it a shape she could trust.
Airmid came forward before the team left.
She did not give some grand speech about coming back alive.
She checked each person's emergency potion, made sure the anti-curse tags sat where they could actually be reached, and reminded them what symptoms mattered.
When she reached Rayleigh, she paused longer than she had with the others.
"If someone suffers the same kind of injury as Lott, bring them back to me after stabilizing them enough to move," she said. "Do not try to complete the treatment inside the passage unless leaving them alone would kill them."
Rayleigh nodded. "I'll keep it light."
Airmid gave him a look.
He sighed. "I'll keep it light even if the wound looks interesting."
"Better."
Welf muttered around the biscuit, "Healers are scary."
Tsubaki slapped him on the back. "Took you long enough to notice."
Airmid continued arranging supplies as if she had not heard them, though the faint lift at the corner of her mouth gave her away.
Finn lifted one hand, and the joking faded without needing to be killed.
The room had done what it needed to do.
Everyone had breathed, eaten something, complained, and remembered they were still people before walking into the dark.
Then they moved.
...
The old passage beneath Daedalus Street was narrow, damp, and unpleasant in the way old underground places always were.
Guild workers had opened the first sealed gate before dawn, then pulled back to the treatment point.
Beyond it, the corridor sloped downward between walls stained by age and old repairs
The lantern stones gave steady light, but the glow did not travel far.
It clung to armor, faces, and the nearest patches of floor, leaving the corners ahead looking thicker than they should.
Gareth took the front with his shield angled slightly so it would not scrape against the wall.
Finn followed just behind him, small and calm, eyes moving over the floor, the ceiling, the cracks, and the dust.
Rayleigh stayed near the middle with the marker pouch, close enough to reach either side if something went wrong.
Riveria walked beside him, her staff ready but her magic held carefully in check.
Strong magic might bother the residue if the same thing that hurt Lott was nearby, and Riveria understood restraint better than most.
Alise, Kaguya, and Ryuu covered the rear.
They did not look like a neat formation from a training manual, but they moved well together. Alise watched the path ahead like she wanted to drag the enemy into daylight by the collar.
Kaguya paid attention to places honest people forgot to check, especially cracks, corners, and the space behind every shadow.
Ryuu listened more than she looked, with Haineko at her side and a thin touch of ash drifting near the floor whenever the air shifted.
Rayleigh set the first marker after fifty paces.
He drove it into the wall and filled the groove with a fine thread of spiritual power.
The mark pulsed back to him, weak to anyone else, but clear in his own senses.
Finn watched closely. "How reliable is the signal?"
"In a normal passage, reliable enough. Down here, I'll trust it more after the walls prove they aren't petty."
Gareth chuckled. "I have known many enemies in my time, but a petty wall is new."
"It breathed at a survivor," Rayleigh said. "I'm comfortable insulting it."
Alise looked at the marker with curiosity. "So this is like a spiritual string?"
"That's close enough," Rayleigh said. "Think of it as me tying a thread to the wall. If the path moves, or if something cuts the thread, I'll feel it."
Kaguya smiled. "A trail of invisible string in a tunnel that dislikes visitors. Charming."
"You can say it in a way that makes anything sound worse."
"That is one of my better talents."
Ryuu slowed a few steps later and lifted her hand slightly. "There's air coming from the right."
Everyone stopped moving as one group.
According to the Guild map, the passage should turn left up ahead.
The right wall had no marked opening, no chamber, and no reason to breathe. Rayleigh moved closer, crouched, and brushed dust away from the floor with the edge of a tool.
A seam appeared beneath the dirt, thin and nearly hidden, running along the base of the stone.
Gareth tapped the wall lightly with his gauntlet.
The sound came back dull.
Riveria frowned. "That is too shallow for solid stone."
"Then our wall has been lying to the Guild for years," Rayleigh said, setting another marker near the seam.
"Or someone opened it recently and covered the signs badly enough that we can still catch them."
Alise leaned in, anger already warming her voice. "Can we open it?"
Finn answered while keeping his eyes on the stone. "After Rayleigh checks whether touching it will do to us what it did to Lott."
Rayleigh placed a second marker higher on the wall and connected both with a faint line of power.
"I'm going to nudge the seam first. If the wall tries anything clever, do not touch the dust."
Kaguya tilted her head. "There goes my plan to lick the masonry."
Alise stared at her. "Why would you even say that?"
"To make the warning feel unnecessary."
"It was already unnecessary!"
Ryuu's ash drifted near the seam, and her teasing expression faded into focus. "The dust is moving inward."
Rayleigh formed a small repulsive field over the crack.
"Bakudō #8: Seki."
A flat pressure pushed against the seam, and the dust along the floor slid backward into the crack as if the wall had drawn in a slow breath.
Alise's face tightened. "That's the same as the survivor's story."
"Close enough," Rayleigh said.
Rayleigh placed a third marker beneath the first two, then fixed all three together so the opening could not shift too easily once it moved.
He did not like how the wall reacted to spiritual power, but the reaction gave him a grip on it, and sometimes that was the best anyone got.
He pointed two fingers at the seam. "Hadō #1: Shō."
The push struck the hidden mechanism.
The wall resisted at first, then scraped inward with a low grind.
A cold breath rolled over Riveria's barrier, bringing the smell of wet stone, old blood, and something bitterly chemical.
The hidden doorway revealed a narrow corridor sloping down at an angle that did not make much sense.
Its floor looked steep, but the visible distance stayed short.
Lantern light stretched oddly along the stone, and if Rayleigh looked too long at one spot, the edges of the passage seemed to slide.
Alise stared into it, her hand already near Engetsu.
"People went through here."
"Maybe," Finn said. "Or the route wants us to think so."
She grimaced but kept herself still.
Rayleigh took out the sealed strip of Lott's bandage and held it near the doorway.
The trace inside twisted toward the corridor at once, ugly and eager.
"This connects to the wound," he said. "Whatever hurt him either came through here or left the same pattern behind."
Riveria's grip tightened on her staff. "Then we follow the original limit."
Finn nodded. "Next stable point only. Mark every ten paces. If the way behind us changes or we lose two markers, we withdraw."
Alise drew a slow breath. "Understood."
Kaguya glanced at her. "I will be right behind you."
"I know."
"I mean that as reassurance and a threat."
"That too."
Ryuu touched Haineko's hilt. "I'll watch the dust. If the air moves like it is carrying a voice, I will say so."