The Count of Aldenvarre had not been invited to a dinner party in forty years, because he had a reputation, and the reputation preceded him into rooms in the way that cold air preceded a window opening.

Dr. Mira Solenne had no time for reputations. She was a physician — the first woman to hold such a licence in the province, which had required a fight she was still winning — and the summons to Aldenvarre Castle had come in the form of a letter from a man who described his condition as an affliction of the blood that defies conventional medicine and who offered a fee that was very considerable and unconditional.

She took the case. She took her medical bag and her most professional expression and she went to the castle in the November dark, which was dramatic, but not everything could be helped.

The Count opened the door himself. This was unusual for a man of his station, and she noted it. He was tall in a way that filled doorways, pale in the way of someone who spent no time in the sun, with black hair and the kind of eyes that registered light differently from ordinary eyes. He looked at her with an expression that was not quite what she'd expected from a man known for menace.

He looked surprised. And then, briefly, something that was not surprise at all.

"Dr. Solenne," he said.

"Lord Aldenvarre," she said. "Where would you like to conduct the examination?"

His affliction was not, in any technical sense, an affliction. She arrived at this conclusion over the course of an hour's examination in which he was cooperative, precise, and clearly educated about his own condition.

"You know what you are," she said, when they had exhausted the pretence.

"Yes."

"Then you know I cannot treat it."

"I know that." He was seated in the examination chair she had commandeered from a writing desk. He had the posture of someone accustomed to physical stillness as a state. "I did not write to you for treatment."

"Then what for?"

He looked at her with those light-registering eyes. "Company," he said. "And someone who would not run."

She looked at him for a long moment. The castle was warm — he kept good fires, she'd noted, which was not strictly necessary for him, which meant he'd done it for her. The appointment had been for an examination. The fee had been paid.

"I'll stay for the evening," she said. "And you'll tell me everything about your physiology. For science."

Something happened in his expression that was relief going somewhere more interesting.

"Gladly," he said.

He was approximately three hundred years old, which he reported with the specific flatness of a fact he had made his peace with. He had spent the intervening centuries doing what very long-lived people apparently did — reading, travelling, observing the progression of human knowledge with the particular interest of someone who would still be here to see where it led.

She asked about haematology. He answered in more technical detail than she'd expected, because he had been corresponding with a physician in Vienna for twenty years on the topic, under an assumed name, which made her laugh.

"You've been publishing in the literature," she said.

"Contributing," he said. "On specific questions."

"Under what name?"

"A. Von Valdren. The A stands for Aldric."

She thought about the Von Valdren papers, which she had read, which had been extraordinarily useful.

"You wrote the paper on haematic oxygen binding," she said.

"Yes."

"That paper changed how I understood three different conditions."

"I hoped it might be useful," he said. "For someone. Eventually."

She looked at him across the fire. Three hundred years of concealment, and a pseudonymous scientific correspondence with Vienna, and good fires for a guest he hadn't met.

"Why did you write to me specifically?" she said.

He was quiet for a moment. "You were the only physician in the province willing to take a case described as medically anomalous. Everyone else declined."

"I see."

"And," he said, "I had read your published work."

She looked up. She had published two papers, both of them controversial, both under her own name because she had decided on that policy and was sticking to it regardless of the field's opinion.

"I have read your paper on the misdiagnosis of hysteria as a catch-all for symptoms physicians could not otherwise classify," he said. "It was the most precise piece of medical writing I have read in twenty years."

She looked at him. The fire. The castle. Three hundred years.

"Lord Aldenvarre," she said.

"Aldric," he said.

"Aldric." She set down her medical bag. "I find I'd like to stay longer than this evening."

Something shifted in his face — the composure of three centuries moving aside for something that had not had room in a long time.

"As long as you like," he said. "I have nowhere to be."

She stayed three days, which extended to a week, which her patients managed without her because she sent word and they trusted her and also several of them had been relieved to have a rest from her opinions.

They talked — through the nights, which suited him, and through the days, in which he occupied himself with correspondence and manuscripts and she occupied herself with his library, which was extraordinary. She conducted further examinations with his cooperation and wrote extensive notes that she was going to have to decide very carefully how to use.

On the fifth evening, the conversation stopped being about science.

"You're not afraid of me," he said.

"I observed that about myself early on," she said. "I found it curious."

"And now?"

"Now I think I understand it." She looked at him across the fire, which she had started to think of as theirs. "You are the most careful person I have met. You keep fires you don't need. You published work that could have exposed you because it might help people. You've been alone for three hundred years and you wrote to a physician rather than simply—" She gestured vaguely. "You could have compelled someone."

"I don't do that," he said, with a flatness that was completely convincing.

"I know. That's the point." She looked at her hands. "You chose."

He looked at her for a long time. The fire.

"Mira," he said.

"Yes," she said. Same word, different weight.

He crossed the room. He was very close when he stopped — close enough that she could feel the temperature of him, which was different but not cold, and look at his eyes at close range, which were doing the thing with the light.

"I would like to," he said, carefully, "and I need to know if—"

"Yes," she said. Before he finished. Because she knew what she was saying yes to, all of it, and she had made the decision on the second day and was simply waiting for him to ask.

He kissed her with the care of someone who had been alone for a very long time and was treating this as the significant event it was. She kissed him back with the directness of a woman who had spent her career fighting for the right to her own opinions and was applying that same directness here, which he responded to with something that might have been relief if relief could be expressed at that temperature.

She said his name when he said hers. The fire was very warm.

The bite, when it came — with her full and explicit knowledge and consent, which she had expressed clearly and which he had asked about twice, which she had found both appropriate and something she was going to think about for a long time — was not at all like she'd theorised. She had expected it to be clinical, a medical event she had catalogued in advance. It was not clinical. It was — she revised her notes mentally — it was the most specifically embodied experience of her professional and personal life, which said something either about the nature of the act or about Aldric, and she suspected it was Aldric.

She held him tighter and said his name once more, in the tone that meant I am revising my prior understanding of this phenomenon.

Afterwards, in the firelight, she felt perfectly well, which she also catalogued.

"You'll need to eat something," he said.

"In a moment," she said. "I have questions."

He made a sound that was, given the context, extremely fond. She sat up and found her notebook.

The castle was very warm. Outside, November did its business. Inside, three hundred years of careful solitude were becoming something different.

She wrote six pages of notes before she went to find the kitchen.

He read them while she ate, and said, "Your observation on the haematic heat exchange is correct," and she looked at him across the kitchen and thought: this is what it is to have found the right person. Even if the finding was November, and a castle, and medically unprecedented.

She could work with unprecedented. She had been doing it for years.