The first thing Alan noticed about the Starfall Observatory on Tuesday night was that someone had cleaned it.

He stood in the doorway with the cold wind at his back and his hand still on the latch, and for a moment he was almost convinced that he had come to the wrong tower. The cushions that had lain heaped in a crumpled rainbow on the rug had been plumped, and sorted by color, and stacked in three tidy piles against the wall. The chalk proof, abandoned halfway through its second line, had been scrubbed from the floorboards. The loose papers were squared. The glass vials stood in a perfect row on the long table, labels outward, in order of size. A broom leaned against the bookshelf. Even the brass telescope had been polished, and its slit of night sky lay open above it like an eye.

-- You have tidied, -- he said.

-- I have not tidied, -- said a voice from the middle of the room, in a tone of the deepest offense. -- I have merely rearranged for efficiency.

She stood beside the table with her hands folded inside her enormous sleeves, as upright as a stalk of wheat. It was the first time he had ever seen Priscilla stand without leaning on something. Her hair had been combed. The crooked silver lens hung level on its chain. She looked exactly like a woman who had spent six hours removing every object from a room in the hope that, with nothing left to look at, she would be forced to look at the one thing she had been avoiding.

-- It is a symptom, -- she said, after a pause.

-- Of what?

-- Of you. -- She lifted her chin. -- You have a way of arranging things when you are agitated. I have been observing it for three weeks. I decided to run a small experiment. I wished to see whether the behavior was transferable.

-- And is it?

-- Apparently so. -- She looked around the spotless room with distaste. -- It is dreadful. I hate it. I cannot find anything. -- A pause. -- Close the door, please.

He closed it. He pressed his palm to the cold oak, and spoke to the quiet at the back of his mind.

-- All of you, if you will. I know it is a great deal to ask.

-- I will stand outside, -- said Nyx, at once. -- I will not look.

-- I am asleep, -- said Helga, with great firmness.

-- I will close my eyes, -- said Valeria. A short stiff pause. -- I have nothing more to say about it.

-- I will, dear, -- said Seraphina. She did not ask to leave a crack. It was a very small thing, and she said nothing more, and when the window shut, it shut all the way.

The pressure in his head eased, as it always did, like stepping out of a noisy room into a cold hall. He turned. Priscilla was standing exactly where she had been, with her hands in her sleeves, looking at him with enormous violet eyes.

-- I lied to you, -- she said.

-- I beg your pardon?

-- In the library. -- She said it very quickly, as though it were a piece of hot metal she had to put down. -- You asked whether I had looked. I said I had looked at the ceiling. I said I was a very honest person. It was a lie. I looked. I looked through the slit I had told you I would close, and I saw the book, and I saw page forty-one, and I saw what was written in the margin, and I saw you cover it with your hand and tell Seraphina that it was an index. -- She drew a ragged breath. -- I have not slept since. I have tidied a tower. I have reorganized four hundred and eleven books. I have been trying to find a way to say this that does not make me sound like a woman who has been spying on a student, and there is not one. I was spying. I am sorry.

-- Senior Priscilla.

-- Do not tell me it is all right.

-- I was not going to.

-- ... Good. -- She blinked. -- That is, I appreciate that.

He crossed the room slowly, and sat down on the nearest stack of cushions. It was very odd to sit on something so neat. After a moment, she sat on the opposite pile, with her knees drawn up and her sleeves pulled over her hands, and they looked at each other across the clean floor.

-- It was my father's handwriting, -- said Alan.

She did not move.

-- The pencil. The words. -- He kept his voice low and even. -- The way the sevens are crossed. I have a birthday card in a shoebox in my dormitory, from when I was seven. It is written in the same hand. I did not realize it at first. I knew only that it was familiar. And then I saw the sevens, and I knew. -- He took a breath. -- I covered it because I did not know what it meant. And because it was mine. I did not want it to be anyone else's, until I understood. I am sorry I lied to Senior Seraphina. I do not think I can say why, even now.

-- You are afraid it will make her worse, -- said Priscilla.

-- Yes.

-- You think she will try to keep you from looking.

-- Yes.

-- She might. -- Priscilla did not smile. -- It is what I would do, if I loved someone and thought the thing he sought might hurt him. It is a very old failing. -- She stopped. -- I did not say that. Forget I said that.

-- I did not hear anything.

-- Thank you.

The wind pulled at the dome. The brass telescope ticked in the cold.

-- I told you in the observatory, -- said Priscilla, very slowly, -- that I had seen a hollow shape once, in the margin of a manuscript written by someone I knew. I said that I thought it had been his idea. I said I thought he had left it unfinished.

-- Yes.

-- I did not tell you whose manuscript. -- She had gone quite white. -- I am not going to tell you tonight. I do not have the right. It is not only my story. But I will tell you what I can. He was my friend. He was the only person in my whole life who was my equal, in the old sense, a person with whom I could argue until dawn and neither of us would be wrong. We worked together. In secret. On things that were, ah. -- A faint, mirthless smile. -- On things that were not permitted. And one night he drew that curve in the margin of a page. A single ring. And he said, if it can be built, it will answer, and then he laughed, because he did not think it could.

-- It answered, -- said Alan.

-- Yes, -- said Priscilla. -- I believe it did. -- She pressed her fingers against her mouth. -- But he is dead, Alan. He has been dead for a very long time. And your father, I do not know what has become of your father, but he drew the same curve. He wrote beside it, in pencil, a warning. In a book that no one should have been able to find. I cannot make that a coincidence. I have tried. I have tried all week.

-- You want it to be one.

-- I want it more than anything, -- said Priscilla. Her voice cracked. -- I want to be wrong. Do you understand? It would be so much easier. If it is a coincidence, then the world is only a world. If it is not, then someone has been walking these same roads for a very long time, drawing the same shapes in the same margins, and nobody told me. -- She laughed unsteadily. -- I do not like to be left out of things.

He did not know what to say. He sat very still with his hands on his knees, and the ring on his finger had begun, faintly, to hum.

-- May I examine it? -- said Priscilla. She said it formally, almost shyly. -- The structure. With the ring in contact. I have a measurement I would like to take. It is not dangerous. I have the backup. I have written the conditions. I will abide by every article. But I will not begin until you say yes.

-- Yes, -- said Alan.

-- You do not wish to hear the procedure?

-- You will tell me as you go.

-- ... I will, -- said Priscilla, and for a moment looked startled, as if she had been handed a coin and told to keep the change.

She did it slowly, and well. She drew out the little brass lens on its copper ring, and lit a small lamp, and had him sit quite still with the band of grey metal resting against his breastbone, held there by a thread of cloth. She did not touch him. She held the lens six inches from his chest and murmured numbers under her breath. A pale violet light rose in the glass. The hollow beneath his ribs brightened, answering, a silver circle with a darkness at its center, and the ring on his finger rang back, a small clear note, and the two sounds braided together into a single steady tone.

Priscilla did not breathe.

-- Oh, -- she said, very softly. -- Oh, that is, I did not expect. -- She moved the lens a fraction of an inch. -- The metal is not only tuned. It is coupled. It is feeding back. When the ring sounds, the chamber answers. When the chamber sounds, the ring answers. They are exchanging a signal. It is a closed loop.

-- Is that dangerous?

-- It is the opposite, -- said Priscilla. Her eyes were very bright. -- It is stabilizing you. The loop damps the oscillation. It is a governor. -- She laughed, breathless. -- Helga has built you a governor out of three copper bits and a bad temper.

-- She said it was scrap.

-- She is an extraordinary liar. -- Priscilla lowered the lens, and the hum faded, and her face was transfigured, flushed with something that was almost joy. -- Do you understand what this means? Do you see? A hollow chamber, if it is tuned, if it is coupled to something that can hear it, does not merely hold. It does not only contain. It answers. It responds. It becomes a thing that is in conversation with the world.

-- You said a resonator.

-- I said a resonator. I did not say what it could do. -- She gave a small, incredulous shake of her head. -- It is a very old idea. It is the oldest idea. The first time I read it, I thought it was a metaphor.

-- It sounds like it.

-- It sounds like a metaphor, -- said Priscilla, quietly, -- because that is how people say the truth when they do not want to be burned for it.

He did not know what to answer. He only sat very still, and the faint silver ring in his chest hummed on, like a bell that has been struck and has not yet stopped.

-- There is one more thing, -- said Priscilla.

-- What?

-- I will not say it tonight. -- She did not look at him. -- It is only a thought. It is not yet a finding. I would be embarrassed to say it out loud, before I am certain. I will tell you when I know.

-- All right.

-- You are not going to press me?

-- No.

-- Why not?

-- Because I would like to be someone who is told things when the person is ready, -- said Alan. -- Not before.

Priscilla opened her mouth, and closed it. A faint dull flush rose along her cheekbones.

-- That is, -- she said. -- That is a very unfair sentence.

-- I am sorry.

-- No, you are not.

-- A little.

-- ... Tea, -- said Priscilla, abruptly, and stood up. -- I will make tea. It is the only thing I know how to do in a crisis. Sit there. Do not tidy.

-- I would not dream of it.

-- You looked at the shelf.

-- I was observing.

-- You were considering.

He folded his hands and looked at the ceiling. She went to the corner, where a small copper kettle sat on a spirit stove, and began to make tea with the loud, clumsy, absent-minded movements of a person who did not usually do it herself. A cup clattered. A spoon fell. There was a sound of something being spilled, and a small muttered curse that he decided not to hear.

He sat on the cushions and let his eyes wander across the neat, strange, spotless room, and it was then that he saw it.

The sugar jar stood in the corner by the stove, beside the kettle. It was a squat glazed pot with a cork stopper. It had been there since his first visit, and he had noticed it then, because it was the only object in the whole tower that had a label. Sugar, it said, in a firm round hand, and under it, in smaller letters: for emergencies. On his first visit, it had been three-quarters full. On the evening after the jeweler, when she had held the ring in her palm, it had been nearly empty. Tonight it was empty.

-- Priscilla, -- he said.

-- Hm?

-- How many spoons do you take in your tea?

-- One. -- She did not turn around. -- Occasionally two.

-- Tonight?

-- ... One.

She set a cup in front of him, steaming, and took the other for herself, and sat down on her cushion with a small tight thump. He lifted the cup. It was nearly syrup. It was so sweet that his teeth hurt, a thick, cloying, unbearable sweetness, as though somebody had tried to make a cup of tea out of candy.

He drank it anyway. He drank all of it. He set the cup down on the floor between them.

-- It is five, -- he said. -- Five spoons, at least.

-- It is, ah. -- She picked up her own cup and looked into it. -- It is a matter of taste.

-- You pour it sweet when you are frightened, -- said Alan.

She went quite still.

-- I did not know, -- he said, slowly, -- until I saw the jar. On the night of the jeweler it was empty. I thought nothing of it. Tonight, again. And your notes from that first week. You had written, in the margins, the amount of sugar you used, beside every entry. It was only a figure. But the figures were highest on the nights you recorded an irregularity in the structure. -- He took a breath. -- You make your tea sweeter when you do not know what is going to happen.

For a very long moment, Priscilla did not say anything. She sat with her knees drawn up, and her cup between her hands, and her large violet eyes fixed on him, wide and dark and very bright, behind the crooked lens.

-- You have been reading my notebook, -- she said.

-- It was open on the table.

-- That is a very thin defense.

-- I know.

-- It is also, -- said Priscilla, in a voice that had gone strangely small, -- an extremely accurate observation. -- She set the cup down in her lap. Her hands were not quite steady. -- Nobody has ever noticed that. In eight hundred years. I did not know it was a thing that could be noticed.

-- It is only a pattern.

-- It is a very private one.

-- I will not say anything to the others.

-- That is not why I am upset, -- said Priscilla. She laughed, a short, helpless, wavering sound. -- I am upset because I find that I do not mind. I would have minded, a month ago. I would have been appalled. I would have called you impertinent and taken your readings and left you in a cupboard. And now I only. -- She pressed the heel of her hand against one eye. -- I find that it is rather a relief.

-- To be noticed.

-- To be known, -- said Priscilla, quietly, -- in a manner that does not end in a book.

The wind moved across the dome. The telescope ticked. Down in the town, a clock struck ten, a thin sweet note.

-- Frost, -- said Priscilla.

-- Yes?

-- I am going to say a thing, and I would like you not to answer it. -- She looked at her hands. -- I would like to be your friend. In the old sense. The sense in which one argues until dawn. I do not know how it is done. I have only done it once. And I made a very poor job of the ending. -- She gave a thin, shaky smile. -- But I would like to try again. If it is permitted. With conditions.

-- I would be glad of it, -- said Alan, gravely. -- I will draft them in the morning.

-- You will draft them tonight, -- said Priscilla. -- I will not sleep otherwise.

So they did. They sat on the clean floor with a lamp between them and wrote it out, a single sheet, in his small hand and her large scrawl, in alternating lines. It was the strangest document either of them had ever composed. It said that neither party would conceal a finding from the other without stating that she was doing so. It said that either could ask for a halt in the conversation for any reason. It said that arguments were permitted until dawn, but not past it. It said that tea would be made by turns, and that nobody would be required to drink more than one cup if it was too sweet. And at the bottom, in her enormous looping hand, she wrote: Priscilla is, on reflection, not a specimen. And then she crossed it out. And wrote beneath it: Alan is not a specimen. And then, after a long pause, in very small letters, almost too small to read: Neither am I.

She handed it to him. He read it. He folded it carefully and tucked it into his breast pocket, beside the pencil.

-- Thank you, -- he said.

-- Do not thank me, -- said Priscilla. -- It is a very low bar.

-- It is a high bar, -- said Alan. -- You have simply never been asked to clear it.

She did not answer. She looked at the floor for a long time. When she raised her head, her eyes were bright and wet, and the corner of her mouth was trembling with something that might have been laughter and might not.

-- I have a gift for you, -- she said at last. -- For the trial. Wait there.

She went to the table, and came back with a small stoppered vial, filled with a faintly luminous violet liquid. She put it in his palm and folded his fingers over it.

-- It is the stabilizer, -- she said. -- The one you asked about. I have revised it. -- She cleared her throat. -- I tested it, again. This time, I think, properly. The sample size is one. The subject is me. The outcome is that I am alive. The confidence level is, ah, moderate.

-- ... Moderate.

-- It is a very honest number. -- She smiled, a small, shy, crooked smile. -- Drink it only if you are desperate. And if you do, I would like to know how it tastes.

He closed his hand around the vial. It was warm.

-- Thank you, Priscilla.

-- It is nothing.

-- It is not nothing.

-- No, -- she said, very softly. -- I suppose it is not.

The great wind turned the dome, and the stars wheeled through the open slit of the sky, hard and white and bright. He sat with her in the small clean room for a long time. They did not say much. When it was time, he rose, and she saw him to the door, and stood on the threshold with her arms wrapped around herself.

-- Tomorrow, -- she said. -- The forest.

-- Tomorrow.

-- Be careful. -- She hesitated. -- And, Alan. If you find, in the forest, that you need to be unbound. That it would be easier. That it would be better for everyone. -- Her voice was very low. -- Do not decide anything until you have talked to me.

-- Priscilla, I...

-- It is only a precaution.

-- All right.

-- Promise me.

-- I promise, -- said Alan, a little bewildered. -- I will talk to you first.

-- Good. -- She let out a long breath. -- Good night.

She closed the door softly. Alan stood alone on the steps of the tower, with the wind in his hair and a vial of moderate confidence in his hand, and the very strange feeling that he had just been handed a key without being told what it opened.

At the bottom of the steps, a small shape detached itself from the shadow of the wall, and fell into step beside him, and said, in an unusually gentle voice, -- Well. That went better than I feared.

-- You said you would not listen.

-- I did not listen. -- Nyx's shoulder brushed his, lightly. -- I stood very close to the keyhole and thought about something else. -- A pause. -- She is going to be very bad at being friends. You know that.

-- I know.

-- She is going to be wonderful at it.

-- I know that too.

-- Good, -- said Nyx. -- Then you are ahead of her. -- She tossed a boiled sweet into the air, and caught it, and held it out. -- Here. For the walk.

He took it. They went down the hill together through the cold, with the stars wheeling above them, and the whole sleeping academy lay below them, quiet and silver, waiting for dawn.