The cold came gradually, then all at once.
For the first day out, Hearth’s warmth followed them, though its light had dropped off the ports when they left the ring’s shadow: a residue, the heat the ship had soaked up while it sat in the yard’s bay and the heat that the lamp’s reach still threw out into the dark this close to Cinder. The cabin was cool but not cold. Mara slept a few hours in the left-hand seat, the rattling one, wrapped in her coat.
When she woke, her breath was smoking.
Sera was already up, or had never slept. She stood in the narrow passage between the cabin and the bay with a hand lamp, waiting.
“We’re past Hearth’s reach,” she said. “From here to Lorn’s, it’s just us and whatever the heater can do. Which isn’t much. Get up. Bring the key.”
She walked Mara down the feed lines.
The Tern’s guts ran along the bay’s starboard side and under its deck, a tangle of pipes and lines in different colors and thicknesses, clamped to the ribs, disappearing through bulkheads, coming up again in unexpected places. Every few meters, a valve. Some were big wheels the size of a dinner plate. Some were small brass taps no bigger than a thumb. Each had a stencil beside it on the hull, white paint on grey, most of the letters worn half away.
“Name it,” Sera said at the first one.
Mara looked at it. A blue line, a brass wheel. She looked at the stencil: C—B— FEED.
“Cabin,” she said. “Cabin air feed.”
“Good. How many turns to close?”
“I don’t—”
“Four and a quarter. Count them when you close it. If it closes in three, something’s in the seat.” Sera moved on. “This one.”
A red line, a lever valve. Stencil worn almost to nothing.
“Engine,” Mara said. “Engine coolant.”
“Engine fuel. Coolant’s the green. You’d have blown us up.” Sera sounded less angry than resigned, as if she had expected it. “Look at the color, then the stencil, then the line. All three. Not one.”
Mara looked again. Red line. A faint F in the stencil. The line ran aft toward the engine compartment, not toward the radiator. She had gone by the lever’s shape, which looked like the coolant levers in Tavin’s yard.
“Fuel,” she said. “Engine fuel.”
“This one.”
“Water.” She checked the color, the stencil, the line. “Potable water. To the cabin tank.”
“And this?”
A big wheel on a fat grey pipe low on the hull, with a stencil in red, still bright, as if someone repainted it often: DUMP.
“Dump,” Mara said. “Emergency dump. For—” She stopped. “For what?”
“For when you need to get rid of something fast. Fuel, coolant, air. Whatever’s on fire.” Sera put her hand on the wheel. “You don’t touch this one unless I tell you, or unless I’m dead. If I’m dead, you’ll know when to touch it.”
They went down the whole ship. Cabin, engine, water, dump. Heater, ballast, hydraulic, brake. Mara got two more wrong, both times by trusting one sign instead of three, and both times she caught herself before Sera did, from the stencil, and said the correction aloud. Sera said nothing about that either. She said “Good” or “Next” and moved on.
At a bend in the feed line low on the port side, near the engine bulkhead, they stopped.
The line here was a heavy black hose, reinforced, carrying fuel from the main tank to the engine’s injectors. It bent sharply around a frame and met a fitting, a steel coupling with a threaded seat, and the fitting was white with frost. Ice had formed on it in a thick crust, and as Mara crouched beside it, she heard it: a tick. A small sharp sound, every few seconds, regular. Tick. Tick. The metal of the fitting contracting in the cold, and something inside it shifting with each contraction.
The graft gave it to her more clearly. A high thin note under the tick, wavering, and at each tick a small catch.
“That’s a patch,” Mara said. She leaned in. Under the frost she could see it: the fitting had been rebuilt, badly, with a seat that was wrong for the coupling, packed with some kind of putty to make up the difference. “That’s not the right part.”
“No,” Sera said.
“Why not?”
Sera was quiet. Then: “Because I sold the right part. The spare fittings. Two ports back. To a mining crew who needed them to keep a drill running, and who paid me enough to buy fuel to get here.” Her voice stayed level. “So the engine’s patched around a real shortage. That’s the Tern. It’s patched around a lot of real shortages.”
Mara bent to the fitting. The putty in the seat was hard with cold and had begun to crack. Each time the metal contracted, the seat shifted a hair inside the coupling, and a hair more of the putty crumbled, and the tick came. In a day, or two, or a few hours if the cold got worse, the seat would shift far enough to open a gap, and fuel would spray out of the fitting onto the frozen engine bulkhead.
She stood up and went to the bay’s spares locker. It was a steel cabinet bolted to the bulkhead, full of the leavings of a hundred repairs: bolts, washers, odd lengths of wire, rags, a broken gauge, a box of springs of various sizes. She sorted through the springs. She found one, a short stiff coil of spring steel, a little wider than the fitting’s collar, from some long-dead valve.
She brought it back. She did not explain. She worked the spring over the end of the coupling and down onto the fitting, around the outside of the collar, so that its coils pressed inward on the collar from all sides. Then she turned it, slowly, screwing it down along the collar like a nut on a bolt.
One turn. The tick came.
Two turns. The tick came, fainter.
She put her ear close to the fitting. Three turns.
The tick stopped.
She held still, listening. The high thin note in the graft had steadied. No catch. The spring’s pressure was holding the seat against the coupling from outside, so that when the metal contracted, the seat could not shift. The cold could do what it wanted; the seat would stay where it was.
“Stop there,” she said.
Sera was crouching beside her. She had been watching the whole time without a word. Now she looked at Mara.
“You can hear it stop?”
“I can hear it change,” Mara said.
Sera looked at the fitting. She reached out and put her thumb on the seal, where the seat met the coupling, and pressed, and held it there for a slow count, the way Tavin held his thumb on a weld. Then she took her thumb away and looked at it. Dry.
She did not say well done. She said nothing about Mara’s ears, or the spring, or the fact that the tick she had presumably been listening to for days had stopped.
“Good,” she said. “Next valve.”
They finished the round. It took most of the morning. By the end of it Mara could walk the length of the Tern and name every valve by its color, its stencil and its line, and say how many turns closed it, and which ones she was never to touch.
That evening Sera came out of the cabin carrying her own bag.
She carried it past Mara into the bay and set it down on the deck beside the crate, and went back into the cabin and stripped the blanket off the bunk, the one against the bulkhead nearest the drive, the bunk that held the engine’s heat through the wall, and carried that out too. She dropped it on the deck beside her bag.
“The warm bunk’s yours,” she said. “Until we land.”
“It’s your bunk.”
“It’s the bunk nearest the drive. It holds heat. The deck doesn’t.” Sera spread her blanket on the cold steel by the crate. “You are not sleeping on a cold deck to prove a point.”
“I wasn’t going to—”
“You were going to sleep in the rattling seat again and tell me in the morning you were fine.” Sera lay down on the blanket with her back to the bulkhead and her arm over her eyes. “Go to bed.”
Mara went to the bunk. It was warm. The wall behind it was warm with the drive’s heat, and the mattress held it, and she lay down under the net and pulled her coat over her and felt the warmth come up into her back, and she was almost asleep before she remembered.
She sat up and took out her column notebook and found a clean page. She wrote the date, the Directorate’s date and then beside it, small, Pell’s real one, as near as she could reckon it. Then she wrote: Tern. Fuel line, port side, at engine bulkhead. Patched seat, wrong part. Scrap spring over collar, three turns. Tick stopped. Feed pressure and the figure from the gauge.
The page faced the household note she had jotted from her mother’s book: bank the stove at the ninth bell. Her own repair on one side. Her mother’s house on the other.
She left them like that and lay down again. Through the wall the drive hummed, and the fitting at the bulkhead held, and all night long the tick did not come back.