Day 7 of 30.
"The east relief valve," Qian said, with his hand on the wheel and his eyes on Lin Yan. "Where does its line go?"
"Threefive checked it," Lin Yan said.
He believed it when he said it. Threefive had called the plan efficient, and efficient had sounded like checking, and he had been tired and his arm had hurt and he had wanted the three hundred stones so badly that he had heard the word he needed and stopped listening.
Qian looked at him a moment longer, then nodded, slowly, and turned the wheel.
They closed the east relief valve at the first bell of the morning.
For one hour, it was perfect.
The old furnace roared awake like an uncle woken from his afternoon sleep, and the pipes groaned and knocked and banged and then, all at once, went smooth. Hot water poured out of the nine dragons' mouths into the pools, steaming, and the old men in the water sighed as if they had been waiting their whole lives for exactly this, and one of them started to sing, badly, and nobody stopped him.
Madam Luo stood at the top of the stairs with tears in her eyes. "My dragons! My dragons are breathing again!"
Bao danced round the boiler room, banging into things. "First day! First day and it's hot! Three days she said, and it's the first day! Put that on the board! Somebody put that on the board!"
Lin Yan leaned against the wall with his left arm hanging at his side. It had held the wrench against the old pipe for as long as it takes to drink a cup of tea while Qian changed the valve, and now it was throbbing as if it had grown its own heart and the heart was angry with him.
He smiled anyway.
Only Old Qian kept a straight face. He had his palm flat against the big feed pipe and his eyes half closed, like a doctor listening to a chest.
"Too fast," he muttered. "The pressure is rising too fast."
"That's the plan," Lin Yan said. "More water in, more heat."
"More water in from where?"
Lin Yan opened his mouth, and found nothing in it, and closed it again.
He had told Qian that Threefive checked. Threefive had been asked for the cheapest heat. Nobody, not him and not the jade, had asked where the water came from, and the question sat there in the warm boiler room between them like something with teeth.
---
The first vent went at the second bell.
It was a drain cover in the middle of Lotus Lane, fifty steps from the bathhouse. It lifted into the air with a bang like a cannon and spun away over the rooftops, end over end, and behind it came a column of white steam as thick as a tree trunk, roaring.
Then the drain cover in Willow Lane went.
Then the one outside the tea shop, and the tea shop's cat, which had been asleep on the warm pipe as it always was, came out of the door like a shot from a sling.
People came running out of their houses screaming. Steam was pouring out of every gutter and every crack and every drain along four streets, hissing and roaring, so thick you could not see the other side of the lane, and the cobblestones were hot enough to feel through the soles of your shoes. The cat shot past Lin Yan with its tail straight up like a flagpole and was gone.
"What is happening?!" Madam Luo shrieked.
Old Qian was already moving, faster than any seventy-year-old man had a right to move.
"The east relief valve!" he shouted. "That line feeds more than the bathhouse! Open it! Open it now!"
Bao ran for the valve and grabbed the wheel and pulled, his whole body leaning back on it, and the wheel did not so much as twitch.
"It's stuck! The pressure's holding it shut! It's like pulling a mountain!"
Lin Yan ran to help. He grabbed the wheel with both hands and heaved, and pain went through his left arm like a knife going in at the elbow, and he screamed out loud and let go, and fell against the furnace, and the furnace was hot.
Qian looked at his arm. Then he looked at his face.
"You lied to this old man yesterday," Qian said flatly.
"Yes," Lin Yan said. His arm was shaking from the shoulder down and he could not make it stop. "Yes. I'm sorry. It can't hold. It couldn't hold yesterday."
For a moment Qian looked as if he would hit him, and Lin Yan would not have blamed him. Then he turned away and started shouting orders into the steam, and his voice was bigger than his body.
"Bao! Go to the Hall, get Mei, get Lin Xiao, get everyone! Madam Luo, get your customers out, out, out! Everyone out of the buildings on this line! Wet cloths on your faces!"
Bao jumped onto his chair. "Chair! Go to the Hall!"
The chair shot straight up and flew east, very fast, with great confidence. The Hall was west.
"THE OTHER HALL!" Bao screamed, and disappeared over the rooftops still screaming.
---
Lin Yan stood in the boiler room with the furnace roaring beside him and took Threefive out of his pocket with hands that would not keep still.
"Threefive. The east relief valve. Where does that line go?"
This time the answer was slow, and quiet, and came without any lists.
"I apologize. You asked me for the cheapest way to make the water hot. I answered that question. I did not look for where the relief line goes. I should have told you I did not know."
"Where does it go?"
"Checking the old city maps in Lin Xiao's archive." There was a pause that felt much longer than it was, with the pipes knocking overhead. "The east relief line connects to four streets, the tea shop cistern, and an old channel under the canal. That channel ends under the great red bridge. It is the district's pressure release. When I told you to close the valve, I closed the district's safety door."
Lin Yan shut his eyes.
He had asked the wrong question, exactly the wrong one, the same mistake as the puppet on the first morning, the same mistake Coaching Sir had screamed at them about every week for four years, and this time nobody was laughing and there were no cabbages.
"Can we open it from somewhere else?"
"The channel has a second gate at the red bridge," Threefive said. "The gate is held by the district's water ward."
"Who holds the ward?"
"The Bridge Saint."
---
By the time they reached the canal half the Lantern Quarter was out in the streets. Somebody shouted that it was the Sleeper's doing, and somebody else shouted that the Sleeper had better be ready to pay for it, and a third person shouted that the Sleeper had predicted it, which did not help anyone.
Steam was rising from the whole east end now, as high as the lanterns, turning the morning white and wet. Mothers were carrying children. Old men were carrying birdcages with the birds shrieking inside them. Somewhere a bell was ringing and ringing, and nobody seemed to know who was ringing it or why it would not stop.
Mei came running down the canal path with ink still on her hands and a roll of paper under one arm she had forgotten to put down, and Lin Xiao was right behind her, barefoot, her hair half tied, the rubber band still on her wrist.
"Ge! What did you do?"
"I asked the wrong question," Lin Yan said. "I'll explain later. Help Qian clear the houses on Lotus Lane."
Lin Xiao looked at his face for one second, no longer. Then she turned and ran back toward the steam without a word, and Mei went after her.
The great red bridge stood over the canal like a gate into the sky, its two towers painted the deep red of old temples, and fog hung round them as it always did, even on clear days, as if the bridge made its own weather.
On the rail at the middle of the bridge sat a spirit.
She looked like a gentle young woman made of red-gold light, sitting with her legs dangling over the water and her hands folded in her lap, watching the fog drift.
"The Bridge Saint," Qian panted, catching up behind them with one hand pressed to his side. "Human Dao lineage. Very old. Years ago the Human Dao healers turned one of her threads all the way up, to study it. The thread was the bridge thread. She has believed she is the bridge ever since. Human Dao offered to fix her. She refused. She likes being a bridge." He coughed. "Who wouldn't."
Lin Yan ran up the bridge steps with his lungs burning and his left arm swinging uselessly against his side.
"Saint! Bridge Saint! Please! We need you to open the relief gate under the bridge!"
The spirit turned her head and smiled at him, and it was the kindest smile he had ever seen on anyone, and it had nothing at all behind it that was listening.
"Hello!" she said. "I am the great red bridge. My towers are two hundred and twenty-seven meters tall. My main span is one thousand two hundred and eighty meters long. How can I help you today?"
"The relief gate! The water pressure! The whole east end is boiling!"
"On foggy days," the Bridge Saint said happily, "my towers disappear into the clouds, and people say I look like a road into heaven. Would you like to hear about my suspension cables?"
Lin Yan grabbed the rail with his good hand. "Please. Please, Saint. There are children in those houses."
"My cables contain twenty-seven thousand five hundred and seventy-two wires each," said the Bridge Saint.
Behind him, far across the canal, the drain cover outside the Nine Dragons Bathhouse blew straight up into the sky and did not come down where anyone could see.
A child was screaming on the rooftop of the tea shop, standing right at the edge, with white steam boiling up on every side of her.