“Rope,” Sera said, before Mara could look at the needle.
Mara turned. Sera had come down the red paint from the door and was standing behind her with the rescue line in her fist, taut between them, and her other hand held out, palm up.
“I’m reading a gauge,” Mara said. “I’m not working the heart.”
“You’re kneeling over a pipe full of cold from the dark side of a sun. You said so yourself.” Sera kept her hand out. “Your mother’s rule. First page. Never work without a witness. I’m the witness. So you keep your count out loud, and I keep the gauge, and if anything changes, I say so, and if I say stop, you stop.”
Mara looked at her for a moment. Then she took Tavin’s rope habit and Sera’s line together: she reached back and wrapped the slack once around her own wrist, so that if Sera pulled, she would feel it before she fell.
“Start,” Sera said.
Mara began to count. Her own heartbeats, by feel, under her breath, the way Tavin had counted them off his wrist clock in the test room. One. Two. Three. She had no idea how fast her heart was going in the suit; faster than in the yard, she thought. She counted anyway.
She looked at the gauge.
“Ninety-four,” she said. She kept her eyes on the needle. She took her notebook from her thigh pocket with her free hand, opened it against her knee, and wrote it, 94, before she said anything else. Then she said it again, aloud, from the page. “Ninety-four on the gauge.”
“Ninety-four,” Sera repeated. She was watching the needle over Mara’s shoulder.
Mara looked up at the ceiling.
“Orison. Ninety-four. What’s yours?”
The grille was quiet. Then a soft crackle, short, like a page turning.
“My last measurement for this valve,” Orison said, “is ninety-four.”
Mara kept counting. Fourteen. Fifteen.
“Your reading agrees with my last measurement,” Orison said. It sounded, almost, pleased. Then the pleasure went out of its voice, and something more careful came in. “I should tell you. I am not certain my last measurement was mine.”
“What do you mean?”
“I have a reading of ninety-four in my record. I do not have a record of taking it. It may have been taken by the last smith. It may have been taken by me, before I forgot taking it. It may have been taken by a sensor that no longer works.” A pause. “But your gauge and my record agree. Two measurements, by two different means, saying the same number. That is the most I have been able to say about anything in this forge for a long time.”
Mara sat back on her heels. Sixteen. Seventeen. She kept counting. Behind her Sera had not moved; the line between them stayed exactly as taut as before.
It was such a small thing. One number. A needle pointing at ninety-four, a voice in a ceiling saying mine too. She had found a hundred numbers in the yard that agreed with other numbers and never thought twice about it. But she understood, kneeling there, that this was the first time the forge had believed her. It had not trusted her with anything or opened any doors. It had believed her. Her gauge had said a thing, and the keeper had checked the thing against its own memory, and they had agreed, and so the keeper knew that when she said a number, the number was real.
One correct reading. It was where everything started.
“Venn.” Sera’s voice. “Your wrist.”
Mara looked down. On her wrist, under the suit’s cuff, where she had moved it from her collar when the suit’s neck ring went on, the Tern’s link clip was blinking. A small amber light. A message, relayed from the Tern docked at the ring above, which had relayed it from the long relay at Lorn’s dome, which had relayed it from Cinder.
“Read it,” Mara said. “I can’t take my eyes off the needle.”
Sera leaned over and pressed the clip, and a small flat voice, the Tern’s reader, read the message aloud through the speaker.
“From P. Venn, Rusk’s yard. One. Are you warm? Two. Did you write the pressure down before you said it? Three. Who is the keeper?”
Sera looked at Mara. Mara stared at the blinking clip.
“How does he know there’s a keeper?” Sera said.
“I told him,” Mara said. “Last relay. From the dock. I said the forge had a keeper and I’d tell him more when I knew.” Twenty-two. Twenty-three. She looked at the needle. Still ninety-four. “Tell him. In order. Can you send it?”
“Short,” Sera said. “The relay’s thin this deep.”
Mara answered in order, and Sera typed it on the clip’s small keys.
“One. Warm enough. I’m in a suit. Two. Yes. I wrote it first. Ninety-four. Then I said it. Three.” Mara stopped.
She did not know how to say what the keeper was. A voice. A machine. A clerk alone with its files. Something the Founders had left behind to keep the forge, which had kept it so long it had forgotten why.
The clip blinked again before she could finish. Pell had sent a second message on the heels of the first, as if he had known she would hesitate.
“Good,” the reader said. “Then say the third one to me too.”
“He means,” Mara said, “say who the keeper is. To him, and not just to myself.”
She thought about it. Twenty-nine. Thirty.
“Three,” she said, and Sera typed. “It’s a voice that forgets. It asks for codes and then apologizes because it can’t remember which ones are real. It writes things down so it doesn’t have to remember them.” She paused. “It’s still the most honest thing I’ve met down here.”
Sera typed it. She sent it. She kept her opinion of it to herself.
Above them, the ceiling grille was silent. Mara wondered if Orison had heard, and decided it must have; the clip’s reader had spoken aloud in its chamber. It said nothing.
Mara took up her notebook from her knee. She had started a new page on the flight from the dock, and at the top of it she had written, in her measuring hand, LORN, and underlined it. Below that heading there was nothing yet but the date. She wrote now: Lowest chamber. Cold valve (shadow chamber feed). Gauge: 94. Orison’s last record: 94. Agree. And beside it, smaller: Orison not sure the record is its own.
She looked at the pipe running out of the valve’s body and into the wall beside the closed door. “Orison. What does this valve feed? Where does the cold go after it?”
“To the quench,” Orison said. “The final cooling. When a heart is folded, it must be locked, and it is locked against a measured pulse of cold drawn from the lamp’s shadow. This valve carries that cold to the cradle in the next chamber.” A pause. “If this valve fails, there is no measured cold. If there is no measured cold, nothing can be locked.”
Mara thought of the chalk on the yard wall. LISTEN. FOLD. QUENCH. And Tavin’s correction, the morning she said it back to him: against a measured cold. Not the cold. A measured cold. If you don’t know how much cold, you don’t know what you’ve locked.
This was the measured cold. This pipe, with its frost and its falling needle. Whatever the forge could do, whatever her mother’s notebooks described, it would all come to nothing if this valve leaked itself empty, because there would be nothing to lock the work against.
“Then it’s not a small repair,” she said.
“No visitor has ever thought it was a large one,” Orison said. “Most of them walked past it.”
She was at forty-one heartbeats.
“I’m going to stop the count,” she said. “I haven’t touched anything. I’ll start again when I do.”
“Stop,” Sera said, and Mara stopped.
She looked at the gauge one more time before she took it off. And as she looked, the needle moved.
Only a sliver. It dropped from ninety-four to just below ninety-four, so little that she would not have seen it if she had not been staring straight at it.
She held still.
The hiss at the collar went on, steady. The frost went on creeping across the pipe. The pressure was falling. The cold in this pipe, whatever it fed, wherever it went, was leaking out of the joint faster than it was coming in, and the number that the keeper and her gauge had agreed on was already wrong.
“It’s falling,” she said.
“How fast?” Sera asked.
“I don’t know yet. That’s why I’m writing it down.”
She wrote the new number in her notebook, beneath the old one. A little less than 94. She wrote it as exactly as she could read it, and put the time beside it, and drew a short line between the two numbers, to show which way they were going.