The mason's name was Goro, and he had the hands of a man who had spent forty years arguing with stone.
He arrived at sunrise, as Aine had promised, and spent the first fifteen minutes of their meeting walking the flat ground above the vent with his arms crossed and his expression locked in professional disapproval. He kicked at the pale mineral stone. He crouched and pressed his knuckles against the surface the same way Ryu had pressed his palm, reading something in the resistance. He stood, looked at the fissure, looked at Ryu, and said nothing.
"Well?" Ryu asked.
"Ground's solid under the clay. Two meters down you've got a shelf of consolidated limestone, runs the length of this flat." Goro kicked the earth again. "Good foundation. Unusual heat."
"That's the point."
"Building a cookhouse?"
"A bathhouse."
Goro went quiet for a moment. Not the silence of a man who didn't understand. The silence of a man who understood perfectly and was deciding whether that was his problem.
"Lord Karashima," he said finally.
"I've been told."
"You've been told the word. You haven't been told the weight of it." Goro looked at the village below, where morning smoke was beginning to rise. "Three years ago a merchant tried to sell clean water from a wagon. Karashima's men overturned the wagon on the second day. Merchant left the district the same night and didn't come back."
Ryu said nothing. He was watching the vent, the thin consistent curl of steam catching the early light.
"I'll need the first course laid by the end of the week," he said. "Fieldstone for the outer walls, flat limestone for the floor. I'll handle the water routing myself."
Goro looked at him sideways. "You're not going to argue with what I just told you?"
"I heard you. The merchant was selling water. I'm building infrastructure." Ryu pulled out his tape measure. "There's a difference. One is a product Karashima can confiscate. The other is a building on unclaimed land, and buildings have legal standing."
He didn't actually know if that was true here. But he'd said it with enough confidence that Goro had started mentally calculating stone quantities, which was the reaction he needed.
"Fifty coppers a day," Goro said.
"Forty and I source the limestone myself."
"Forty-five and I bring my nephew. The boy's useless but he can carry things."
"Done."
Goro spat on his palm and held it out. Ryu shook it without hesitating. Different world. Same ritual. Some things apparently traveled.
The girl arrived two hours later, while Ryu was sketching the floor plan in the dirt with a stick.
She came up the hill at a pace that suggested she was running late for something she'd already decided was her destiny. Seventeen, maybe eighteen, with her hair escaping from its tie in three different directions and a look of absolute uncomplicated enthusiasm that Ryu found immediately exhausting.
"You're the one building the water house," she said, not quite a question.
"Bathhouse."
"Same thing." She set down the bundle she was carrying, which appeared to contain, among other things, a large pot, two blankets, and a live chicken that registered its opinion of the situation loudly. "My name is Fumiko. Kasuri Aine sent me."
Ryu looked at the chicken.
"It's for lunch," Fumiko said.
"Does Kasuri-san know about the chicken?"
"She said bring supplies. I supplied." Fumiko looked at his dirt sketch with the focus of someone who had decided to be competent through sheer enthusiasm. "Is that the floor plan? The changing room should be bigger. Women need more space to change than men do because of the layering. My mother always said that. Also, where does the steam go? If you trap the steam in a closed room it gets humid and the wood rots. You need vents. Do you know about vents?"
Ryu looked at her.
"Yes," he said. "I know about vents."
"Good. Aine said you might not know local construction customs. I know all of them. My uncle built the miller's barn, so I have experience."
"A barn."
"A very well-ventilated barn."
Ryu pointed at the northeast corner of his sketch. "Changing rooms go there, separated by a partition. You're right that they need space. There will also be a cooling room and an herb room off the main chamber." He looked up. "Can you source herbs?"
Fumiko's expression shifted to something more serious, the first indication that there was genuine capability under the noise. "Medicinal or aromatic?"
"Both. Lavender, mint, anything with antiseptic properties. Mountain cedar if it grows here."
"Cedar grows above the east ridge. The rest I can get from the market or trade with old Haruno in the lower village, she grows herbs and she hates Karashima's tax collectors, so she'll deal." Fumiko was already pulling a piece of folded cloth from her bundle and writing on it with a stub of charcoal. Making a list. "How much do you need for opening?"
Opening. He hadn't thought in those terms yet. He'd been thinking in terms of construction phases.
"Give me an estimate for forty clients a day, rotating in shifts."
Fumiko calculated. He could see her doing it, silently, her lips moving slightly. "Two weeks to source the volume you'd need. If we start drying and preparing now."
"Start now."
She nodded briskly and kept writing. The chicken had escaped from its bundle and was investigating the mineral stone near the vent with philosophical detachment.
Ryu turned back to his floor plan and felt, for the first time since landing face-down in the mud, something that resembled forward motion.
The ground moved at midday.
Not violently. A shiver, brief and directional, running from the vent toward the northeast corner of the planned foundation. Goro's nephew, whose name turned out to be Kenji and who was in fact not useless but simply very quiet, stopped carrying stone and looked at the ground.
Goro kept working.
Ryu crouched and pressed his palm flat against the earth.
The vibration was not geological. He knew geothermal movement, knew the low steady pulse of water under pressure, knew the particular frequency of a shifting rock shelf. This was none of those things. This was rhythmic in a way that the earth wasn't. Rhythmic in a way that suggested intention.
Something is moving down there, his professional brain reported, calm and precise. Something that is aware of the vibration we're creating on the surface.
He stayed crouched for a moment, palm flat, listening through his skin.
The vibration stopped.
Then, very faintly, it came back. Different pattern. Shorter pulses, three in a row, then silence. Then three again.
He stood up.
"Goro. Is there a known cave system under this hill?"
Goro set down his chisel. "Old stories. Children's stories." He paused. "My grandfather said the hill used to be called Fuchi no Yama. Depth-mountain. Said there were things living below that traded with the village in the old times, before Karashima's grandfather took the district."
"What kind of things?"
Goro picked up his chisel. "Children's stories," he said again, which was not an answer.
Ryu looked at the ground. The vibration had gone quiet but the quality of the silence felt attentive, the way a room feels when someone has just stopped talking and is waiting to hear what you say back.
He pulled his wrench from his belt. Held it by the head. Knocked the handle against the stone three times.
Paused.
Knocked three more times.
Waited.
From below, through the soles of his boots, through the limestone and the clay and whatever came after that: three knocks. Then silence. Then what might have been, if he was interpreting vibration through stone correctly, something that could only be described as curious.
Fumiko appeared at his shoulder. "Who are you knocking to?"
"Neighbors," Ryu said.
She looked at the ground. Then at him. Then she wrote something else on her list, and he decided not to ask what.
By evening, the first course of stone was laid. The northeast corner stood knee-high, the limestone foundation solid and level, Goro's work precise in the way of someone who had given up on the wisdom of the project and committed to the quality of the execution.
Ryu stood at the edge of the flat ground as the copper light thickened toward dusk and looked at what existed now that hadn't existed this morning.
Below, in the village, a woman was drawing water from the shared well. The rope was still rotting. The water that came up was the same water it had always been, cold and gritty and carrying whatever the earth around it carried.
She looked up toward the hill. She couldn't possibly see him against the light. But she looked up for a moment before turning back to her bucket.
Ryu watched her go.
One month, he reminded himself, for the second time.
The stone behind him held its heat as the air cooled around it, steady and patient, and something below the earth knocked three more times in the dark.