Alan had never been outside after the final bell.

He understood this only when he reached the foot of the boys' wing stairs and found his hand resting on the latch of the side door, unable to lift it. Seventeen years of training stood beside him in the dark, patient and disapproving. Article eleven of the charter: curfew at eleven o'clock, every student in his hall by the final bell, no exceptions. His father's letter, folded in a drawer upstairs: We have never given it cause for correction.

He lifted the latch.

The cold struck him full in the face. The night was very clear, and very still, and the moon stood over the Academy like a lamp somebody had forgotten to put out. The north lawn lay below the steps in one unbroken sheet of silver, and the snow squeaked under his boots so loudly that he was certain it could be heard in the Warden's tower. He kept to the shadow of the arcade wall for as long as it lasted, and then there was nothing for it but to cross the open ground, hunched, quick, with his heart going in his ears like a hammer. It was only when the wind found a gap at his chest that he discovered he had buttoned his coat wrong, one button off all the way down, and he did not stop to fix it.

I am going to stop her, he told himself, with every step.

It was a perfectly reasonable errand. A student of good standing, seeing a classmate set off into the Enchanted Forest alone at night, would naturally take steps. Any sensible person would have done the same. It had nothing to do with a wave across a lawn, or with a single word shaped by a mouth too far away to hear.

The boundary stones stood at the edge of the trees, a long row of waist-high gray pillars carved with ward-sigils that glowed a faint, steady gold. Beyond them the forest rose like a wall, black and enormous, its tops dusted with frost. And on the third stone from the left, swinging her boots, with a lantern at her feet and a basket beside her, sat Elen Joy.

She saw him and went up off the stone like a spring released.

"You came!"

"I came to stop you," said Alan, with as much dignity as a person could muster who was breathing like a hunted deer and wearing his coat askew.

"Of course you did." She was beaming. She did not seem even slightly alarmed at being found. "You buttoned it wrong."

"It is dark."

"It looks very brave." She tilted her head. "Are you cold? I've got a spare scarf, it's only a little bit chewed."

"Miss Joy."

"Elen."

"It is after curfew," said Alan, firmly. "You are about to cross a restricted boundary without a teacher. That is a breach of article nineteen."

"Article twenty."

"I beg your pardon?"

"It's twenty. Nineteen is the one about the library cats." She said it kindly, as a person corrects a small child's pronunciation. "Twenty-one is the curfew one."

"Twenty-one is the dress code."

"It's the curfew one, and also something about hats."

He stared at her. He had a dreadful, creeping suspicion that she was right. He closed his mouth.

"I am going to escort you back to the girls' wing," he said instead, "and if you refuse, I shall be obliged to report the matter."

"You'd have to say where you saw me." She picked up the lantern, and its warm light swung across her face and the freckles on her nose. "Which is out here. After curfew. With me."

Alan opened his mouth. There was a flaw in that. It was a very small flaw, and he did not enjoy it.

"That is irrelevant."

"It's a lovely flaw, though." She grinned. "Here's an offer. Come for an hour. Just an hour. If at the end of it you still want to report me, I'll walk you to the Warden's door myself and knock."

"That is not a reasonable offer."

"It's the only one I've got."

She stepped over the line of stones, light and neat, and the nearest sigil flickered once as she passed and settled. She stood on the far side with the lantern lifted, waiting, not pulling, not pleading. Just waiting, the way she had waited in the corridor outside Alchemy.

Alan took a step forward to seize her by the sleeve.

That was all it was. He meant to seize her sleeve and walk her back across the grass by main force if necessary, and he was already reaching out when he realized that his foot had come down on the far side of the stones. He had not decided to cross. He had simply been so intent on the girl that the line had slipped beneath him like a stair in the dark.

Behind him, something groaned.

It was a long, slow, wooden sound, like a great ship settling. He turned, and saw the bracken at the edge of the stones fold over itself, and roots as thick as his arm lift out of the snow, and knit across the place where he had just been standing in a tight, dark, interlaced lattice. The gap closed with a soft crunch. The stones glowed gold on the other side of a wall of wood.

"Ah," said Elen.

"What was that?"

"Right. Yes. I should have said." She winced, and it was the most contrite he had ever seen her look. "It doesn't like to be left halfway. If you cross, you've got to be walked out again. The paths rearrange behind you. It's a bit like a cat. If you don't finish stroking it, it takes offense."

"You are telling me that I cannot leave."

"I'm telling you that you can't leave alone." She held out the lantern. "Stay in the light. Don't step anywhere the light doesn't. I can walk us out, I promise. I've done it loads. I just can't do it yet, the forest hasn't finished saying hello."

"This is," said Alan, in a voice rather higher than usual, "a very irresponsible arrangement."

"Yes," said Elen. "I know. Hold on."

She took his sleeve.

The path went in under the trees, and the night changed.

It was a different dark in there, thicker and older and strangely alive. The trunks stood close together, black and ridged and wet with frost, and the lantern pushed a small warm bubble of light through them that stopped at the edge of everything. The silence was not silence at all. It was a murmur, low and continuous and everywhere, like a great many people in the next room trying not to be overheard. Alan heard it in the branches, and in the snow-laden brush, and underfoot, in the roots that coiled across the path like sleeping animals.

"Do you hear that?" he whispered.

"That's them talking."

"Who?"

"The trees. They're discussing you." She said it perfectly seriously. "It's all right. They do that to anyone new. They'll settle."

He wanted very much to say that trees did not discuss. But a root the width of a man's waist had just slid across the path behind them, with a sound like a sigh, and he found that he had stopped wanting to say anything at all.

The path turned. It turned again, in a way no path had a right to, so that the bend that should have led left curled round and led right, and somewhere in the second twist his sleeve slipped out of her fingers.

"Oh, no, don't. Stay." Her hand shot back, caught his, and held it. "Sorry. I should have asked. It's just that if I lose you here I'll have to explain it to a tree. Is that all right?"

His hand lay in hers, and he looked straight ahead, at the lantern.

"It is a practical measure," said Alan.

"Absolutely."

Her palm was warm and a little rough, ink-stained, faintly dusty with something that smelled of mint. She did not squeeze. She did not hold on harder than she needed to. She simply walked, steadily, a half step ahead, and the whole of his attention narrowed to a single bright point at the base of his thumb where her fingers lay. He counted his own steps. It was something to do. By forty, the murmur around them had begun to soften, as though the forest were leaning in to listen, and by sixty, Elen had started to hum.

It was a very low, tuneless, comfortable sound. And the trees, to his astonishment, answered it. The whispering fell away to a soft rustle. A branch that had been leaning over the path lifted itself, with dignity, out of their way.

They came out into a clearing.

It was small and round and walled with black trunks, and in the center of it stood the largest tree Alan had ever seen. It was hollow, its trunk wider than a cottage, split by a tall dark seam from which a faint pale light spilled. And on its lowest branches, hundreds upon hundreds of them, hung small white flowers shaped like bells. They were opening as he watched. Each one unfurled with a tiny sound, like a breath, and gave off a thread of silver glow, so that the whole tree shimmered in the dark like a ship made of stars.

Alan forgot, for a moment, that he was angry.

"Silverbell," Elen said softly. "They only open at night, when there's moon. They close at dawn, and then they're just ordinary flowers. You can't see them in daylight, not really." She let go of his hand. He felt the absence of it like a draft. "Wait here. I have to ask first."

She walked to the great tree, set down the lantern, and knelt.

She was not in a hurry. That was the first thing he noticed. She put her bare palm flat against the bark and bowed her head, and spoke in a low voice, not the bright bouncing voice he knew, but something quiet and courteous and a little formal, like a girl calling on an elderly relative.

"Good evening, Grandmother. It's me again. I've brought someone with me. He's a bit stiff and he's wearing his coat wrong, but he's harmless."

The branches stirred. A single flower tilted, as if to look at him.

"She says you smell like ink and rules," said Elen, without turning round.

"That is an unfair characterization."

"She says it's not an insult. She says it's a very orderly smell." She was laughing, soundlessly, her shoulders shaking. "She also says you're standing too stiff and should sit down. She likes people to sit."

Alan, after a moment, sat on a fallen log at the edge of the clearing. He did it with a sense of being managed by a ghost.

Then Elen asked for what she wanted.

"May I take twelve, please? Only the open ones. I'll leave the buds, and I won't touch the east branch, I know it's still tender." She waited. The leaves rustled in a long, slow, unmistakable pattern, like a sentence with commas in it. "Thank you. Yes. I know. I'll be careful."

She unstoppered a jar from the basket. She worked with extraordinary delicacy, taking each blossom between two fingers at the base and easing it free so that the silver glow came away without a tear, and laying it down in the glass as if she were putting a child to bed. She counted aloud under her breath. At eleven she paused, looked at the twelfth, found a brown speck on one edge, and left it, and chose another. Alan noticed that she checked each one with her nose before she took it. Twice she stopped to move a small pale snail off a root with the tip of a leaf, murmuring an apology.

When the twelve were done and the jar sealed, she took from her pocket a twist of paper and sprinkled a pinch of coarse salt around the roots, in a ring, and then unscrewed a little flask and let a single drop of water fall onto the bark.

"She likes salt," said Elen, over her shoulder. "Nobody believes me. But she does. It's the only thing I've found that she actually asks for." She bowed her head again. "Thank you, Grandmother. Goodnight."

The whole tree seemed to sigh.

Alan sat on the log with his hands on his knees, and he did not speak for some time.

He had come into the forest braced for a particular sight. He had known what it would look like: a careless girl crashing through the undergrowth, tearing flowers from their stems, snatching what she wanted and leaving whatever mess might follow. He had seen her at the arcade wall with a basket of clinking jars and written down the facts in neat black ink. Careless. Contemptuous of order.

He looked at the ring of salt. He looked at the unwilling snail, now restored to its root. He looked at the twelve silver flowers shining behind the glass, each one counted, each one asked for.

He went back through the list in his head, point by point, hunting the line where he had gone wrong. It was not easy to find. Every item on it was still true. She had come in by the window. She had missed the lessons. She had crossed the boundary without leave. And yet the word at the bottom of the list sat very badly now, like a coat that had been cut for someone else.

"You ask her permission," he said.

"Of course." Elen glanced round, surprised. "It's her tree."

"And if she had said no?"

"Then I'd have gone home and thought of something else."

"You would have obeyed a tree."

"I'd have respected a tree." She wiped her fingers on her coat. "It isn't the same thing."

He thought about that.

It was not an argument he had any ready answer for, and he disliked intensely that it sounded true.

They left by a different path. Elen said the clearing had a back door, and the forest liked to be thanked from both sides, and in any case the way they had come would have rearranged itself by now into something nobody wanted to walk. So they went on through a narrow aisle between the trunks, her lantern bobbing ahead, the basket held tight against her side with its twelve small lights, and her hand reached back and found his without looking, as if it had always known where to find it.

It happened very quickly.

The path bent. The moon went behind a cloud, and in the sudden dark the lantern's light seemed to shrink to a tiny golden bubble, and Alan, who had been counting steps and not looking where he put his feet, took one pace to the left to avoid a root and put his boot down on a patch of pale, soft, innocent-looking moss.

The ground gave.

It did not break. It folded, like a mouth, with a wet greedy sound, and his leg went in to the knee and then the thigh, and the cold of it shocked all the breath out of him. He felt it close around his boot, thick and heavy and clinging, and begin to pull.

Panic took him, immediate and complete. It rose up out of some old place, from before he was a student of good standing, from before he was anyone. The dark. The cold. The weight. A door that would not open and a lantern gone out.

"Alan!"

She had both hands on his arm. She braced herself, boots skidding on the snow, and heaved with a strength he would never have believed a girl her size possessed. There was a loud, sucking, reluctant pop, and the ground let him go. He came out of it all at once, off balance, and Elen caught him against her. Her arms went round him hard, one hand spread between his shoulder blades, the lantern clanking on the ground beside them, and she held him there while he shook.

"It's all right," she said, quick and low and utterly steady, close against his ear. "I've got you. It's all right. You're okay now."

Alan stopped breathing.

It was the voice. It was not the words, though the words were nearly the same. It was the voice, level and warm and unafraid, pitched to carry through weather. A door full of white light. A small shape kneeling in the snow. You're okay now. They're here.

Ten years had passed, and it was exactly the same.

He stood with his face half buried in her scarf, the smell of pine and mint and cold air all around him, and for one long moment he could not tell which of the two of them he was holding on to. The girl in the doorway and the girl in the forest stood one inside the other like nested dolls, and he could not pull them apart.

Elen drew back. She had a hand on each of his arms, and she was studying his face, frowning, with no dimple at all. She was entirely serious.

"You've gone white," she said. "Did I hurt you? I grabbed you really hard, I'm sorry, I didn't mean."

"No."

"You're shaking."

"It is cold."

"Is it your leg? Is it wet? I can dry it, I've got a charm, it only takes a second."

"Elen." He heard his own voice come out ragged, and tried again. "I am quite all right."

She looked at him a moment longer. Then she nodded slowly and let go, one hand at a time, as if checking whether he would stand.

"Mirewort," she said. "The forest keeps it in the paths where it doesn't want people to go. It's meant to be a warning. I should have said." She picked up the lantern and wiped it on her sleeve, and her hand was not quite steady. "I'd have got you out, though. Probably."

"Probably."

"Almost certainly."

He made a sound that was not a laugh, and was not far from one. She glanced at him, and a little of the tension went out of her shoulders.

They sat for a few minutes on a flat stone at the edge of a dry streambed, while he scraped the worst of the mud off his boot and she dried his trouser leg with a quick, practical flick of two fingers that left a faint smell of toasted sugar in the air. The jars sat between them in the basket, glowing softly, twelve small silver stars. Neither of them said anything for a while.

"What are the jars for?" Alan asked at last.

"Something I'm working on." She said it lightly, looking at the lantern. "It's not allowed yet. It might not be, ever."

"Not allowed."

"There's a rule about new recipes. I know. I read it, remember? Article thirty-three."

"Thirty-four."

"Thirty-four," she agreed, and a flicker of the old grin came back. "But what I'm trying to make, I can't tell you yet. Not because it's a secret from you. I just don't know if it works, and I don't want to say it out loud until it does. It feels like tempting something."

"That is exactly the problem," said Alan. "A recipe nobody has reviewed is a recipe nobody can answer for."

"I know."

"If it goes wrong, there is no one to account for it. No one to check your work."

"I know, Alan." She said it gently, with none of the heat he had expected. "I'm careful. You saw me." She looked up at him, and the lantern put two small gold points in her eyes. "Will you tell?"

He thought of his notebook. He thought of four neat lines of Observations and the verdict beneath them. He thought of article nine, and of the Warden's tower, and of his father's square handwriting. He thought of twelve silver flowers, counted, asked for, thanked. And of salt in a ring around a root. And of two arms around him in the dark, and a voice that had said the same thing, in the same way, ten years ago, to a stranger.

It was a great deal to weigh on a stone in the middle of a forest.

"I will not report this," said Alan.

She let out a long breath.

"But I do not approve."

"That's fair."

"And there is a condition."

"Anything."

"You will not enter this forest alone again."

Elen stared at him. She did not say anything for a moment. Then, very slowly, the dimple came, deepening in her left cheek like something rising from beneath the water, and her whole face went warm and astonished and glad.

"Is that a yes to next time?"

"It is a condition. It is not an invitation."

"Presently?"

"Presently," said Alan, with a dignity he did not feel.

She laughed, a real one, low and delighted, which the trees seemed to take as a good sign. And the way out, when she led him to it, lay open and ordinary and quiet, a straight path of frosted bracken running between the trunks, and he did not for a moment believe it had always been there.

The forest let them go at the boundary stones.

The roots that had closed behind him an hour ago opened without a sound. The gold of the sigils spilled out over the snow, and the Academy lay below them in the moonlight, huge and sleeping, its towers dark against the stars. It was still deep night. No bell had rung. In all the world nothing moved on the lawn but the wind, and a long, thin cloud drawing across the moon.

Alan stood on the near side of the stones, in the cold, with the smell of pine still in his coat.

He thought of what he had written in the notebook. He thought of a girl at an arcade wall with a basket and a lantern, and the word he had put beside her. It did not fit. He turned the word over, searching for a better one, and could not find any. He was not even sure there was one. All he knew was that he could no longer say careless, and that nothing had yet come to take its place.

"Which way do you go in?" he asked.

"The trellis. By the girls' wing."

"There is a prefect on that side."

"There's always a prefect." She shrugged, perfectly cheerful. "I've got a trick with the lantern."

"I know. I watched you do it." He hesitated, then said, with the air of a man unlocking something, "There is a route. Through the kitchens. It comes out by the laundry yard, under your wing. No corridor in it is on the patrol."

Elen's eyes went very wide.

"You have a smuggler's route."

"It is a more efficient route."

"You have a smuggler's route, and you're a model student." She pressed the basket to her chest, delighted beyond speech. "Alan Valemont. I'm going to need you to say that again."

"I shall not."

He led her round by the kitchen garden, over a low wall, and through a door he had learned how to lift by its latch without the hinge squealing. They went in single file, past the dark ovens and the sacks of flour, past a shelf where a covered bowl stood with a note propped against it, For the ghost, in a cook's round hand. Elen read it, bit her lip, and made a strangled noise into her scarf. Alan walked on with his ears burning and his eyes fixed straight ahead.

At the laundry yard door she stopped.

The courtyard beyond was black and still, the long wall of the girls' wing rising above it with one window faintly lit on the second floor. Elen stood in the doorway with the lantern turned low and the basket in her arms, her red hair full of pine needles and snow, and looked up at him with her head tilted. She looked, for once, a little shy.

"Thank you," she said. "For coming. And for not telling. And for the condition."

"It is a reasonable condition."

"It's the nicest anyone's ever put on me." She took a breath. "Alan. The other day. I asked what you love and you couldn't say."

He tensed. "I am aware."

"It's all right. I wasn't being clever. I just wanted to know." She shifted the basket. "So I thought I'd go first. I'll tell you what I love, or better, I'll show you. Saturday, four o'clock. The Potions Club, in the east greenhouse. It's open evening for anyone who wants to look." Her smile came back, small and brave. "Come and see."

His first impulse was to refuse. He had a list of reasons, and they were all in order. The second impulse was something he had no name for.

"I shall consider attending," said Alan, "in a professional capacity."

"A professional capacity."

"As your co-author."

"Right. Of course. In that case you should definitely bring the wall." Her grin broke wide at last, the dimple deep and bright. "Goodnight, Alan."

She slipped through the door and was gone, light and quick, and her footsteps faded up some unseen stair. Alan stood in the dark of the laundry yard for a long time, holding a hand that still felt, at the base of the thumb, the warm weight of someone else's, and listened to the sound of his own pulse in the quiet.