The first snow of the year came to Yunmo Pass the way a debt comes due, quietly at first and then all at once.

Bai Qingluo watched it fall from the dispensary window while she counted. Forty-one paper packets of honeysuckle. Nineteen of licorice root. A jar of dried tangerine peel that stood lower than it should, because she had given half of it to the charcoal burner's wife that afternoon and had not charged for it, as she had not charged anyone for anything in three years. She wrote each number in the ledger in a small, upright hand. When she reached the bottom of the page she did what she always did, which was to go back to the top and check the sums, because a mistake in a ledger was only a mistake, and a mistake in a dispensary was something else entirely.

Behind her, the common room of Lanternpine Inn settled into its night sounds. The fire popped and shifted. In the kitchen, Granny Pei's cleaver knocked a steady rhythm against the chopping block, mincing tomorrow's pickled radish for no reason except that the old woman could not sit still when she was worried, and she had been worried for three years. Somewhere overhead a rafter creaked as the cold took hold of it.

The inn stood at the highest bend of the pass, where the road from the river towns gave up pretending to be a road and became a goat track between two shoulders of grey rock. It had forty years of smoke in its beams and a single old pine by the gate from which it took its name, and in deep winter it was the only lit window for a day's walk in any direction. Travelers called it a mercy. Qingluo had stopped calling it anything. It was the place she had been given to stand, so she stood in it.

She closed the ledger and pressed the heels of her hands against her eyes. She was twenty-four years old and she felt ninety. Her shoulders ached from the day's grinding, and the scar across the back of her left hand, a pale, shiny stripe from a decoction she had spilled long ago, had begun to itch the way it did whenever the weather turned. She flexed her fingers until the itch faded, then took the small jade-handled spoon from its hook on the shelf and began the last duty of the night.

Before any herb left her hands, she tasted it. Not a swallow, only a pinch the size of a grain of rice, touched to the tip of her tongue and held there while she counted ten breaths with her eyes closed, listening for anything wrong. Too bitter, too sweet, too sharp, a flatness that should not be there. It took time she did not have, and by the end of every evening her mouth tasted of dust, and she did it anyway, every packet, every time, because there had been a night three years ago when she had not.

She did not think about that night. She had a great many practiced ways of not thinking about it, and the best of them was work. She tasted the honeysuckle. She tasted the licorice. She tasted the tangerine peel, and she was reaching for the Quiet Pine powder, the one with her own seal pressed into the wax, a little sprig of pine in red, when the dispensary door banged open against the wall and the cold came in with a boy attached to it.

"Sister Qing!" A-Du skidded on the boards, his cheeks stung red and his wool cap crooked over one ear. He was twelve and ran every errand the inn had, and in all the months she had known him she had never seen him afraid. He was afraid now. "Sister Qing, there's a man at the gate and he isn't moving!"

She was already on her feet. Her hands found the satchel by the door before her mind had finished the thought, the way a soldier's hands find a sword. She snatched the storm lantern from its peg and went out into the snow with the boy's cap flapping at her heels.

The wind had risen while she counted. It threw handfuls of white against her face and found every gap in her collar, and the snow was already ankle deep on the courtyard stones, soft and swallowing. The old pine at the gate bowed under its new weight. Beneath it, where the lantern light barely reached, there was a long dark shape half buried in the white.

Qingluo ran. She went down on her knees in the drift without feeling the cold of it and set the lantern in the snow beside her. A man lay face down, one arm flung out, his hair spread across the snow like spilled ink. His robe had once been white. Now it was the color of rust and river mud, and the snow around his left side had gone dark and crusted.

"Hold the light," she said, and A-Du took it with both hands, shaking so that the shadows jumped. She got her shoulder under the man's and rolled him over.

His face was the first thing she saw, and for a moment she forgot to breathe. It was not that he was beautiful, though he was, in the severe, over-sharpened way of a blade left out of its sheath. It was that even unconscious, even with his lips gone blue and frost caught in his lashes, he wore an expression of such complete and weary contempt that it seemed to be etched there. A face that had been disappointed by the world for a very long time.

She pressed two fingers to his throat and waited.

The beat came, then nothing, then, after what felt like three of her own breaths, another. She had felt hearts like this before, in men pulled from frozen rivers, hearts that had slowed to a crawl to save what warmth they could. But this was slower. This was the pulse of a sleeping animal, a bear in its den, a thing built to survive winters that would kill a man.

"Is he dead?" A-Du whispered.

"Not yet." She thumbed back one of the man's eyelids to check the pupil, and her thumb went still.

The iris was gold. Not the amber-brown that some people called gold, but true gold, like old brass with a lamp lit behind it. And the pupil at its center was not round. It was a narrow, upright slit, a cat's eye, a thing from the margins of old herbals, in those sections that scholars copied faithfully and no one admitted to believing.

She lowered the lid very gently, as if it might bruise.

"Sister Qing?"

"The cold does strange things to the eyes," she said, in the steady voice she used for frightened patients, and was amazed at how ordinary it sounded. "Later. We'll think about it later. Go and fetch Granny Pei, and tell her to bring the door off the woodshed."

He went, sliding, the lantern bobbing away into the dark, and she was left kneeling in the howling white with the stranger's head in the crook of her arm. She made herself look at the rest of him. The robe was torn along the left flank, the cloth stiff with old blood. Beneath it, when she peeled back the edge, was a gash the length of her forearm, not fresh, days old at least, and fouled. The edges had gone a strange grey-green. Her stomach tightened. Wounds did not do that on their own.

His left hand lay curled against his chest, clenched around something. The knuckles were white. She worked his fingers loose one at a time, and they gave with a stiff reluctance, as though even unconscious he did not want to surrender it. It was a twist of paper, creased and damp. The wax seal on its fold was cracked but whole, and she knew it the way she knew her own handwriting.

A sprig of pine, in red.

She held it close to the light spilling from the inn's windows and opened it with a thumbnail. Pale powder, clumped with damp. She wet the tip of her little finger, touched it, and breathed in.

Quiet Pine. Willow bark, ginger, pearl barley, a little dried pine resin to knit wounds. She had ground the recipe herself and sold it for years to peddlers who carried it down to the river markets in the dozens. It was a good powder, and honest. But beneath it, thin as a splinter at the back of her nose, there was a green bitterness that she had not put there.

She stared at the packet. A hundred like it were out in the world. Any one of them might have ended in this man's sleeve. But a seal was a seal, and a man who clutched a packet in his sleep, who held it with the last of his strength as he walked to her gate, had not come here by accident.

She folded the paper shut, slipped it into her sash, and did not let herself think the thought that was waiting at the edge of her mind.

It took the three of them to carry him in. Granny Pei came puffing through the snow with A-Du dragging the woodshed door behind her, her sleeves rolled to the elbow and her grey braid coming loose, and she did not waste a word. They rolled the man onto the planks and hauled, Qingluo at his head, the old woman and the boy at his feet, and the cold wind threw snow into their faces all the way across the courtyard.

She took him to the herb room behind the dispensary, a small, low chamber where the chimney flue ran through the wall and kept the air dry and warm, where she hung her bundles and where she kept a cot for the worst cases. They heaved him onto it. Granny lit three lamps without being asked. Then she took a pair of shears and cut away what was left of the robe, and for a moment she stopped.

Qingluo, rolling up her sleeves at the basin, followed her gaze.

The man's wrists were ringed with scars. Old ones, pale and puckered, and over them new ones, raw and weeping, as if something had rubbed and rubbed at the skin for a long time and had only recently been taken away. The marks were too even to be anything but the work of iron.

Granny Pei looked up. Her eyes were small, black and sharp, and in thirty years of cooking for travelers on the pass they had missed very little. She did not say anything. Neither did Qingluo.

"Travelers carry odd baggage," Granny said at last, flatly.

"Granny."

"I said nothing." The old woman dropped the shears into the basin with a clatter and went for hot water, and her back, retreating, was as eloquent as any sermon.

Qingluo sent A-Du to bed. He went reluctantly, looking back over his shoulder at the stranger on the cot. At the door he turned. "Sister Qing. Will he die?"

"Not tonight," she said, and meant it like a vow. "And A-Du. Not a word about this to anyone who comes through the gate. Not one."

He nodded, wide-eyed, and was gone.

She worked through the first watch and the second. She cleaned the gash with salt water and then with strong wine, scraped away the grey-green slough that clung to the edges, and flushed it again until the flesh beneath looked clean and red. She stitched it with boiled silk, tight and small, her needle hand steady for the first time all day. She heated her needles in the lamp flame and set them at the points along his arms and chest that coaxed a sleeping heart toward waking, and counted that slow, strange pulse over and over. She spooned ginger broth between his lips a few drops at a time and massaged his throat to make him swallow. She packed hot bricks wrapped in cloth along his sides. Granny Pei brought more bricks and said nothing and went away again.

By the third watch the blue had gone from his lips. His heart had quickened, though it was still far slower than any man's should be. She sat on the stool beside the cot with her fingers on his wrist, in the small circle of lamplight, and let her eyes close for the space of a breath.

It was in that breath that his hand turned over and closed around her wrist.

She did not scream. She would think about that later, a little proudly. But her whole body went rigid, and her eyes flew open, and she found herself looking into his.

He was awake. Gold, in the lamplight, glowing with a faint inner light like the eyes of an animal at the edge of a campfire, the pupils drawn to thin dark blades. His grip was iron. It should have been impossible, from a man who had been dying three hours ago, and yet there it was, every finger a cold, certain bar against the bones of her wrist. He had half risen from the pillow. His face was inches from hers, close enough that she felt the warmth of his breath, close enough that she smelled him: snow and wood smoke, blood, and under it something wild and clean, like cold pine and fur.

She could not have said how long they stayed like that. Her pulse hammered in the cage of his fingers, and she knew he could feel it, and she hated that he could.

"What," he said, his voice a rasp, cracked from disuse, "did you give me?"

"Ginger broth," she said. Her own voice came out thin. "Warm wine to clean the wound. Needles. Nothing else. You're safe. You're at an inn, I'm a healer, you were half frozen at the gate—"

"Before." The grip tightened, not enough to hurt, but enough to make her aware of exactly how much more it could. His eyes searched her face with an intensity that made her skin prickle. "Three nights ago. The powder. The pine. Your seal."

She drew a breath. She could have lied. A lie would have been easy and kind, and he was barely conscious and would not remember it. But she had tasted every herb in her dispensary for three years so that she would never again have to lie about what she had given someone, and the habit would not let her.

"The packet in your hand carries my seal," she said, quietly. "I don't know what was in it when it reached you. There is something in the powder that does not belong there. I think it was added after it left my hands. But I can't swear to it. I won't swear to anything until I've tested it."

He stared at her. Something moved in his face, something that was not quite surprise and not quite fury, a slow, bitter comprehension, like a man hearing the answer to a riddle he had hoped had no answer.

"So it was you," he said softly. "The poisoner of the pass."

The words went through her like a blade through silk. Her mouth opened, though she had no idea what she meant to say.

His hand went slack. The gold dimmed in his eyes, guttered like a lamp starved of oil, and his head fell back against the pillow. His fingers slid from her wrist, leaving a ring of cold that burned.

She sat very still for a long time.

The lamp hissed. Snow ticked at the paper window. Her wrist, where he had held it, throbbed with the ghost of his grip, and she rubbed it absently with her other hand, and found that her fingers were shaking.

The poisoner of the pass.

She had not been called that in three years. Not aloud. But she heard it every night, in the quiet before sleep, in a voice that was her own.

She let herself remember, then, because it was too late in the night to hold it back. A winter evening much like this one. A traveler on her cot, feverish, young, grateful. A lamp guttering, and her own hands trembling with a fatigue so deep it felt like drowning, two days without sleep, a whole ward of the sick behind her. A bowl of medicine she had mixed from a jar she had trusted. A taste she had meant to take, and had not, because her eyes were closing, because there were so many others waiting, because it was the same jar she had used a hundred times. The way his lips had turned, afterward. The sound his breathing had made.

She pressed the back of her scarred hand against her mouth until the memory passed.

She was not going to let it happen again. Not to this man, whatever he was, with his gold eyes and his iron scars and his contempt. If the powder was hers, if she had hurt him, she would cure him. She would sit by this cot as long as it took. And when he could walk, she would open the gate and let him go, and whatever she owed him would be paid. It was the only kind of arithmetic she had left to trust.

The lamp wavered. She rose, stiff in every joint, to trim the wick, and then, because his breathing had grown shallow and a little noisy, she leaned over the cot and loosened the collar of his under-robe to give his chest room.

She froze.

Below his collarbone, just left of center, a mark was burned into his skin. It was the size of her palm, an intricate lattice of tiny characters wound in a knot, written in a script she did not recognize but whose purpose she knew at once, as one knows the shape of a snare. The lines were the red-black of fresh brands. They were faintly warm to the eye, and as she watched, a slow pulse of dull light crawled along them and faded, like a heartbeat made of embers.

She had seen such a mark once before, in a pamphlet that traveled the markets in the lower towns, warning of the wandering exorcists who bound spirits with talismans and dragged them off in chains. She had thrown the pamphlet into the stove. She had not believed a word.

She stood in the lamplight with her hand still raised, and the wind groaned in the eaves, and she understood three things at once. That the man on her cot was not a man. That someone had been hunting him, and had wanted him very badly. And that, of all the doors in all the valleys of the north, he had walked, half dead, to hers.