There was a particular quality to a Friday before an Open Tide, and Tamsin had always loved it.

The harbor held its breath. Fishermen tarred their boots and mended their nets with a quiet, almost religious attention. Dockhands stopped joking. Down at the chandlery, old Pettibone would hang a small hand-lettered sign in the window that said CLOSED FOR TIDE, and nobody would think to ask him what that meant. Even the gulls seemed to go still, and sat in long white rows along the breakwater with their heads tucked down, waiting.

Tamsin had grown up in that hush. She had learned to read it the way other children learned to read faces. She had learned that there were forty-one different silences in Saltwick harbor, and that each one meant something different, and that the one that came the day before an Open Tide was the silence of a held bow string.

Today, for the first time in her life, she could not hear it.

She could hear only her own thoughts, which were loud, and which had been going around in her head since yesterday morning like a trapped bird.

Sit down.

She had said it. In front of Odo, in front of Juno, in front of Corra Venn and half the population of Brine and Bean. She had said it in a voice she had not heard come out of her mouth in seven years, a low, rough, unplanned voice that had slipped past her guard like a thief, and she did not even know why. Ila had been about to leave. It would have been the simplest thing in the world to let her. A tidy exit, a closed door, one less problem.

Instead she had reached out with two words and dragged her back.

Because of the way her face had gone, a small, hunted, naked flinch, the look of a person who had just heard a sentence that had been aimed at her like a harpoon. Because Corra had said careful and smiled that perfectly pleasant smile, and Tamsin had known, with the cold certainty of long acquaintance, that Corra had meant something else entirely.

She did not know what. That was the maddening part. Corra Venn knew something about Ila Sorrel, and Tamsin did not, and she hated it the way she hated a fouled propeller or a ledger that wouldn't balance.

"You're doing it again," said Odo.

She looked up. He stood at the wheelhouse door with a mug in each hand, a stub of pencil behind his ear and an expression of mild, patient accusation. She had not heard him come up.

"Doing what?"

"Scowling at the horizon like it owes you money." He handed her one of the mugs. "Drink that. It's tea. It's not terrible."

"It's always terrible."

"Then drink it anyway." He settled himself against the bulkhead with a creak of old knees. "That girl's in the chart room. Has been since six. I think she's trying to memorize the whole buoy network."

"Good."

"She hasn't eaten."

"She's an adult."

"Aye. That's what they all say, right up until they fall over." He sipped his own tea and gazed out at the water with great innocence. "Might be a kindness, though, if someone went and showed her how it was actually done. Seeing as how the insurers want a deep-water exam before the end of the week, and she's been learning the numbers from a laminated card."

"It's a good card."

"It's a card, Tam."

He very seldom used the nickname. He had been using it since she was six years old and perched on a stack of lobster pots, furiously refusing to wear her life jacket, and it had a way of getting under her ribs. She looked at him for a long moment, and he looked back with eyes as mild and blue and impossible to argue with as a clear sky.

"Fine," she said at last. "I'll do it. But only because the exam is important."

"Of course."

"It's purely professional."

"Naturally."

"You can wipe that look off your face."

"What look?"

She went below. She did not slam the door. She was extremely proud of that.

* * * The chart room was not so much a room as a very large cupboard.

It sat at the aft end of the Lark's lower deck, a cramped, windowless compartment about the size of a prison cell, lined on three sides with cork boards and brass rails and racks of dog-eared paper charts. A single fold-out table stood against one wall, bolted to the steel, and over it hung a battered lamp with a green glass shade that swayed gently with the motion of the boat. The air smelled of old paper, pencil shavings, and the faintest trace of Odo's pipe.

Ila sat at the table with her elbows planted and her head in her hands, surrounded by pages.

They covered the whole surface. Buoy readings. Surge projections. Tide curves, ruled in her own neat, spiky handwriting, and annotated in the margins with tiny cross-references and exclamation marks. A cold mug sat at her elbow with a skin on the surface of the tea. Her hair had come loose, and her shoulders were hunched, and her lips were moving silently as she read.

She did not hear the door.

For a moment Tamsin simply stood and watched. It was an indulgence she would not have allowed herself in daylight, but the cupboard-room was dim and the lamp threw a warm gold circle on the table, and Ila looked so entirely absorbed, so small and serious and unguarded, that the sight went through Tamsin like a splinter under a nail.

She had always done that. Even at nineteen, she had worked with her whole body, the way a child draws. Biting her lip. Wrinkling her nose. Humming a nonsense tune under her breath, so tuneless and so happy that the two of them had once been thrown out of a library for it.

She was not humming now.

"You've got the Greenhead buoy wrong," Tamsin said.

Ila jumped like a startled cat. Papers fluttered. She spun in her chair, one hand pressed to her chest, and stared at Tamsin with an expression of such pure outrage that Tamsin nearly laughed.

"Do you always sneak up on people?"

"You were muttering. I assumed you wanted privacy."

"I wanted peace."

"Same thing." Tamsin crossed the little room in two steps and leaned over the table, a hand on each side of the pages, her braid swinging forward over one shoulder. "Here. The Greenhead buoy runs four minutes behind the Saltwick gauge. It's been out of true since the spring storms. If you use the harbor numbers without correcting it, you'll come up four minutes early."

"The table doesn't mention it."

"The table was printed before the storms."

"That's an extraordinary oversight."

"It's a municipal printer. Extraordinary oversights are their house style." Tamsin tapped the margin of the page with one blunt finger. "Write it down."

Ila wrote it down. Her pencil moved in quick, angry little strokes. Tamsin found that she was standing very close, close enough to see the fine dark hairs curling at Ila's nape, close enough to feel the warmth coming off her shoulder, and she straightened abruptly and took one step back.

"Right," she said. "I'm teaching you."

"I beg your pardon?"

"The insurers want a deep-water examination by Monday. You'll sit it with a clipboard and no electronics, and you'll have to calculate a full Open Tide cycle from raw readings, in your head, in under twelve minutes. Odo says you're learning it from a card."

"The card's perfectly adequate."

"The card is a prayer on laminate." Tamsin pulled out the second stool with her foot and dropped onto it. "I don't care how clever you are. I won't have my boat in the Drift with a pilot who doesn't know why the numbers say what they say. Sit up straight. We start with surge."

It was, she told herself, a perfectly reasonable thing to do. It was a matter of insurance and good practice and the safety of her crew. It had nothing to do with the line of Ila's neck in the lamplight, or the way she bit her lip when she was thinking, or the ghost of a half-smile that had almost, almost, appeared when Tamsin said municipal printer.

Nothing whatsoever.

* * * They worked for three hours.

It was not peaceful. Tamsin did not know how to teach peacefully. She had learned the sea from her father, who taught by shouting, and she had never entirely outgrown the habit. She set problems and snapped corrections. She tossed out figures like a bad-tempered auctioneer, and Ila caught them and threw them back with a tight, furious precision that was entirely her own.

"Surge at Greenhead, plus point six."

"Add the lunar offset. Point two-two."

"Correct for the wind shear."

"Which wind?"

"The one that matters."

"That's not an answer."

"It's the only answer there is. The wind that matters is the one that kills you." Tamsin pointed at the page. "You're looking at the numbers as though they're a puzzle. They aren't. They're a conversation. The sea is telling you what it plans to do, and your job is to listen, not to argue."

"I'm not arguing. I'm checking."

"You're always arguing. You argued with Dell Warrick over a bowline once, for forty minutes."

"Dell Warrick tied it wrong."

"Dell Warrick tied it differently."

"That's what I said," said Ila. "She tied it wrong."

It was ridiculous. It was ridiculous, and the corner of Tamsin's mouth was trying to lift, and she fought it down. She found, to her considerable alarm, that she was beginning to enjoy herself. The cork-lined room had grown warm. The air between them hummed with the old, dangerous energy of two stubborn people who had once been fluent in each other, and every sentence they threw seemed to land a little closer than the last.

"Different problem," Tamsin said. "Falling tide at the Pennywhistle narrows. Wind from the northwest at twelve knots. What's your arrival window?"

Ila's pencil paused.

She said nothing for a moment. Her gaze lowered to the table, and Tamsin saw something move across her face, a shadow, a closing. Her fingers tightened around the pencil.

"Ten to midnight," she said, finally. Her voice had gone quiet. "On the equinox. Low water at eleven fifty-two. The window closes at twelve oh nine."

"That's not the Pennywhistle."

"No."

"That's not any of the numbers I gave you."

"No," said Ila.

The hum had gone out of the air.

Tamsin sat very still. She had a sudden, distinct sense of the room as a small, enclosed space, thirty square feet of cork and cold light, with the whole weight of the Lark hanging over it and the sea moving gently on the other side of the hull. She had heard those numbers before. She had heard them in her sleep for seven years.

Low water at eleven fifty-two. Window closes at twelve oh nine.

It was a night on the shingle. It was cold sand under her palms and the long dark sound of the surf, and her ankle caught fast in something she could not see, and a voice calling her name over and over, a young, desperate, furious voice, saying hold on, hold on, I'm here.

"You remember it," Ila said. She said it softly, without looking up.

"Don't."

"I never forgot. I can recite the whole night. Every number. The surge, the wind, the water temperature. The way the moon was." Her voice cracked slightly. "I memorized it. I think I thought if I knew it well enough, I could, I don't know. Go back. Do it differently."

"Ila."

"I was twenty-two and I thought if I just got the arithmetic right."

"Stop," Tamsin said.

She had not meant it to come out the way it did. It came out raw, cracked in the middle, a sound like a knife dragged across glass, and it fell into the little room with a terrible clarity. Ila looked up. Her face, in the lamplight, was pale and strained and very young.

For a moment neither of them moved.

The boat rocked. The lamp swung on its chain, throwing shadows back and forth across the walls like slow pendulums. And Tamsin, with the cold taste of that old night in her mouth, felt something stir inside her that she had spent seven years burying. A reaching. A wild, shameful, animal longing, to put out a hand and touch her face.

And then, with a sudden clunk, the lights went out.

* * * They sat in the dark.

It was perfectly, absolutely black. The lamp, the corridor bulb, the faint glow from the passage, all of it gone in one stroke, like a hand clapped over a candle. Tamsin heard a distant thump from the engine room, and the sound of Odo cursing at length, and the slow, grinding groan of a generator being told it was unwelcome.

"Power," she said, unnecessarily.

"I gathered."

"It does that. It's the starboard breaker. Odo will have it back in a few minutes."

"Good."

Neither of them moved.

Tamsin could hear her own breathing. She could hear Ila's, three feet away, quick and shallow. She could smell her, too, in the sudden blindness, a sharp clean scent of salt and pencil and warm skin, and she gripped the edge of the table with both hands and told herself firmly to keep her mind on the ceiling.

"Do you have a torch?" Ila asked.

"In my pocket."

"Are you going to use it?"

"In a moment."

A silence fell, very full.

"You don't need it, do you?" said Ila, softly.

"What do you mean?"

"The numbers. I could see it, a minute ago. You didn't look at the page once." There was a faint rustle in the dark, the sound of someone leaning forward. "Surge, tide, offset. You said them all from memory."

"I've been doing this since I was twelve."

"You said them the way you used to say my name."

The words hung in the air like a thrown stone, stopped at the top of its arc.

Tamsin's heart gave a single hard knock against her ribs. She could feel the blood rising in her face, and was fiercely, absurdly grateful for the dark.

"That's not appropriate," she said.

"I know."

"I'm your captain."

"I know." Ila's voice was low and unsteady. "I just. I wanted you to know that I noticed."

She should leave. She should get up and walk out, grope her way along the passage, find Odo and the breaker box and the safe, sensible, clean light of day. She was thirty years old and the master of a salvage vessel and she had sworn, sworn on her father's grave, that she would never let Ila Sorrel get close enough to touch her again.

Instead she sat in the dark with her hands knotted on the table and said nothing, and listened to Ila breathe.

"Tamsin," Ila said.

"What."

"Are you cold?"

She was. She had not noticed until she was asked, but her fingers had gone numb on the steel and her teeth, she now realized, were very slightly chattering. The cupboard-room had always been cold when the heating failed. She felt it creeping up her arms, a thin damp chill like fingers on her skin.

"No," she lied.

There was a rustle. Something warm and heavy fell across her shoulders.

It took her a full two seconds to realize it was a jacket. A sage-green waterproof, still warm from a body, smelling faintly of salt and rain and the ghost of someone's skin.

"I don't need that," Tamsin said, stiffly.

"You're shivering."

"I'm perfectly fine."

"Then it won't hurt you to wear it." Ila's voice was gentle. It was a gentleness Tamsin remembered, and she hated how it undid her. "Take it. I'm hot anyway. It's the pencil."

"The pencil."

"It's very warm pencil."

It was so foolish, so unexpectedly absurd, that a small startled breath of laughter escaped Tamsin before she could stop it. In the dark she heard Ila's answering laugh, short and breathless and incredulous, and for one brief, bright, unbearable moment the whole sorry weight of seven years seemed to lift from the room like fog.

The lights came back.

* * * They blinked at each other, dazzled.

Ila was sitting with her hands in her lap, and her sleeves pushed to the elbow, and her hair in total disarray. Her cheeks were flushed. Her eyes were very bright. She was looking at Tamsin with an expression of such open, helpless, unguarded warmth that Tamsin's heart gave a painful lurch, and she dropped her eyes to the jacket on her own shoulders and discovered, with a hot shock of mortification, that she was clutching the collar.

She let go.

"Thank you," she said, with all the dignity she could muster. She slid the jacket off and held it out. "Here."

"Keep it a minute. You're still cold."

"I'm not."

"Your lips are blue."

"They are not."

"A little blue."

"We're done for the day," Tamsin said, and rose from the stool so abruptly that it clattered against the wall. "Review chapters four through nine of the surge manual. I'll quiz you tomorrow at oh-six-hundred."

"Tamsin."

"And eat something. You look like a ghost."

She did not wait for an answer. She walked out of the chart room with her spine as straight as a mast and her heart beating like a trapped sparrow, and she did not look back, because if she looked back she would have to admit to what she saw.

* * * She took the long way round to the deck.

She went out through the stern hatch, into the cold clean air, and stood at the rail with her hands gripped tight on the steel and her breath steaming in the gray afternoon light. She counted the mooring lines. She checked the fenders. She went to the winch and tested the brake, and then she tested it again. She went to the davit and checked the shackles and ran a hand along the length of the stern line, feeling for weakness, for chafe, for any sign of failure.

There was nothing wrong with it. There never was. It was the best-kept boat in the harbor.

She checked it a third time anyway.

Behind her, a boot scraped on the deck.

"Tam," said Odo, mildly.

"I'm busy."

"I can see that." He was leaning on the bulkhead with his arms folded and his cap pushed back, and he was looking, not at her face, but at the faded yellow oilskin she had hung over the rail an hour ago. Something else hung beside it now. A sage-green waterproof jacket with a small brass pin on the collar, and a faint damp stain on one shoulder where a woman had been pressed against a steel wall.

Tamsin had forgotten she was holding it.

She had carried it all the way up the stairs. She had carried it across the deck. She had, she now realized, hung it carefully on the rail next to her own, side by side, neatly, like a pair of lovers on a clothesline, and she stared at the two jackets swinging gently together in the breeze and felt her face go hot to the roots of her hair.

"That's not," she began.

"She never lent me that jacket," Odo said peaceably.

"It's not mine."

"I know whose it is."

"It's an accident. It fell off a chair."

"Of course it did."

"Odo."

"I didn't say a word." He tipped his cap down over his eyes and wandered off along the deck, whistling a very small, very smug little tune. "Not a word, Captain. I'm only the engineer."

Tamsin glared after him until he disappeared round the wheelhouse.

Then she looked back at the jackets, and the wind lifted the sleeves, and for a moment the empty arms moved toward each other, as though they were reaching.

She turned the key in her mind, and put the thought away, and went to check the lines again.

It was going to be a very long season.