During the time immediately after my father’s change of state, Malcolm told him that his new life would be better than his previous one.

“We’ll never grow old,” Malcolm said. “We’ll survive anything — car crashes, cancer, terrorism, the infinite petty horrors of mundane life. We’ll persist, despite all obstacles. We’ll prevail.”

In Western culture, aging always means diminished power. Malcolm said they’d enjoy freedom from pain — and from love, the curse of mortals. They would live without what he called the ephemera: transitory concerns based on mortal personalities and politics that, in the end, no one would remember.

Malcolm spoke of mortals as if they were vampires’ worst enemies. “The world would be a better place if humans were extinct,” he said.

I took another sip of Picardo, which sent a tingling sensation through my body. “Do you agree?”

“Sometimes I’m tempted to agree.” My father waved his hand toward the shade-covered window. “When you walk around out there, you see so much unnecessary suffering, so much greed and malice. The abuse and murder of humans and animals — unnecessary, yet commonplace. Vampires — some of us — are always mindful of the ugliness. We’re a bit like God in that respect; you don’t recall that line of Spinoza’s, that to see things as God does is to see them under the aspect of eternity?”

“I thought we didn’t believe in God.”

He smiled. “We don’t know for certain, do we?”

But Malcolm didn’t mention the problems, my father said — the terrible urge to feed, the mood swings, the vulnerabilities, and all of the ethical implications of the change of state.

At first my father considered himself no better than a cannibal. Over time, he learned the truth of Bertrand Russell’s belief: by ordering one’s mind, happiness becomes accessible, even to an other.

One night when my father was half conscious, he called for Sara. Malcolm reminded him of it afterward. He said the only right thing was never to see her again.

“There’s a history that you don’t know yet,” Malcolm said. “Other vampires have tried to live with mortals, and it never works. The only alternative is to bite her. You could use her as a donor, so long as you never let her bite you. I personally would be disheartened if you made a woman one of us.” Malcolm was half-lying across a sofa in my father’s room as he said this, very like a character in an Oscar Wilde play — the consummate misanthrope.

At the time, my father thought that Malcolm might be right — the kindest thing would be for him to end his relationship with Sara. He agonized over how to let her know what had happened. How could he tell her what had taken place? What sort of letter could he write?

My mother wasn’t religious in a conventional sense, but she believed in a God among many gods, to whom she could pray in time of trouble. The rest of the time, she mostly ignored that God, as many mortals do. My father was afraid that his news could shock her into some irrational action. He considered never communicating with her again — simply moving to a place where she’d never find him.

When Dennis took over Malcolm’s role as caretaker, my father began to look at the problem differently. Perhaps there were other alternative actions. At any rate, it was clear to him that the matter couldn’t be handled by a letter. No matter what he might write, she wouldn’t believe it — and she deserved to hear an explanation face to face.

Some days, as he grew stronger, my father thought that he and my mother might be strong enough to weather the situation. Most times he felt otherwise. Malcolm had told him some odd tales while he was bedridden, and they persuaded him that any vampire union with a mortal was damned from the start.

So, for the time being, he told my mother nothing.

Surprisingly, Dennis raised the subject. “What will you tell Sara?”

“I’ll tell her everything,” my father said, “once I see her.”

“Isn’t that risky?”

For a moment my father wondered if Dennis had been talking to Malcolm. But then he looked across at his friend — the freckled face, the wide brown eyes — and he realized again all Dennis had done for him. Dennis was holding a vial of blood at the time, preparing to inject him.

“What’s life without risk?” my father said. “Nothing but mauvais foi.”

He reminded me that mauvais foi means “bad faith.”

“We need to spend a little more time with the Existentialists, don’t you think?” he said.

“Father,” I said, “I’d be happy to spend more time with the Existentialists. And I do appreciate knowing these details. I do. But I can’t bear the idea of going to bed tonight still not knowing about my mother, or whether I’m going to die.”

He stirred in his chair, and looked over at my now-empty plate. He said, “Then let’s move into the living room, and you shall have the rest of it.”

In the end my father didn’t have to choose a way to tell my mother what had happened. She took one look at him at the airport, and she said, “You’ve changed.”

Rather than bringing her back to Cambridge, my father took her to the Ritz Hotel in London, and they spent the next five days trying to come to terms with each other. Sara had packed carefully for the trip; she had a distinctive style, my father said, recalling in particular a green chiffon dress that rippled like romaine lettuce.

But she didn’t have any reason to dress up. Instead of going to the theatre, or even downstairs for tea, they stayed in their suite, ordered room service every day, and fought bitterly over their future.

When my father told her about his new state, she reacted as humans are said to react to news of a loved one’s death: with shock, denial, bargaining, guilt, anger, depression, and finally, some sort of acceptance.

(He noted that I had not reacted in those ways to anything he’d told me. That alone, he said, suggested that I might be “one of us.”)

My mother blamed herself for what my father had become. Why had she urged him to come to England? Then she blamed my father. Who had done this to him? Had he caused it to happen? Then she began to cry, and she wept for most of a day.

My father held her when she’d let him, but held her gingerly, worried that she might tempt him somehow. He didn’t trust himself to relax around her.

He told her he regretted the day he’d been born — and then he apologized for using a cliché. He would get out of her life at once, he said, for both their sakes.

She refused to hear it. When her crying stopped, she grew insistent that they stay together. If my father left her, she said, she would take her own life.

My father accused her of being melodramatic.

“It’s you who’ve turned our lives melodramatic!” she said. “It’s you who managed to become a damned vampire.” Then she began to cry again.

“Sara,” my father told me now, “even at the best of times, which this was not, had little talent for reasoned argument.”

By the end of the week, my father felt emotionally and physically exhausted.

Sara won. She went back to Savannah wearing an engagement ring: a replica of an Etruscan ring with a tiny bird perched on it, bought by my father when he’d first arrived in London. A few weeks later, he packed up his things and took a plane home.

He joined Sara in the brick house by the cemetery, which indeed was haunted, and every day they learned new ways of accommodating what Sara called my father’s “affliction.” Dennis stayed in Cambridge, but he mailed my father freeze-dried “cocktails,” the formulae for which were ever-evolving to more closely approximate fresh human blood. This work was the beginning of what would become Seradrone.

After a few months, my mother and father were married in Sarasota, a seaside town in Florida, and later they moved to Saratoga Springs. (Sara retained her fondness for the letter S, thinking it was lucky, and my father indulged her. He wanted to please her as much as he could, to compensate for his condition.)

They settled into the Victorian house. In time, Dennis finished his research at Cambridge and found a job at one of the colleges in Saratoga Springs, so that he and my father could continue to work together. They formed the company called Seradrone and recruited Mary Ellis Root as an assistant; her training in hematology was truly outstanding, my father said. The three of them developed a blood purification method that has enabled transfusions all over the world.

Sara kept busy at first, decorating the house, and tending the gardens and, later, her bees — she set up hives by the lavender patch in the garden. They were (my father spoke with some astonishment in his voice) happy.

But for one thing: my mother wanted a child.

“You were conceived in the usual way,” my father said, his voice dry. “Your birth was a long process, but your mother came through it quite well. She had real stamina.

“You weighed only four pounds, Ari. You were born in the upstairs bedroom with the lavender wallpaper — your mother insisted upon that. Dennis and I handled the delivery. We both were concerned when you didn’t cry. You stared at me with dark blue eyes — far more focused than we expected a newborn’s eyes to be. You seemed to say hello to the world in a matter-of-fact way.

“Your mother fell asleep almost at once, and we carried you downstairs to run some tests. When we tested your blood, we found you were anemic — we’d anticipated this possibility, since your mother was anemic throughout the pregnancy. We spent some minutes debating the best treatment. I even called Dr. Wilson. Then I carried you upstairs again.” Here he lifted both hands, in a gesture of helplessness. “Your mother was gone.”

“Not dead,” I said.

“Not dead. She simply wasn’t there. The bed was empty. And that’s when you first began to cry.”

My father and I stayed up until four a.m., sorting out details.

“Didn’t you look for her?” was my first question, and he said that yes, indeed they had. Dennis went out first, while my father fed me; they’d bought cans of infant formula in case my mother’s breast milk wasn’t adequate. When Dennis came back, he looked after me, and my father went out.

“She didn’t take her purse,” he said, his voice dark with memories. “The front door was ajar. The car was in the garage. We found nothing to suggest where she might have gone. Who knows what went through her mind?”

“Did you call the police?”

“No.” My father left his chair and began to walk back and forth across the living room. “The police are so limited. I didn’t see any point of calling them, and I didn’t care to invite their scrutiny.”

“But they might have found her!” I stood up, too. “Didn’t you care?”

“Of course I cared. I do have feelings, after all. But I was sure that Dennis and I had a better chance of finding her on our own. And —” He hesitated. “I’m accustomed to being left.”

I thought about his own mother, dying when he was a baby, and about what he’d said about bereaved children — how death informs them, marks them forever.

He said he sometimes felt as if a veil hung between him and the world that kept him from directly experiencing it. “I don’t have your sense of immediacy,” he said. “In that, you’re like your mother. Everything was immediate to her.

“When the shock of finding her gone began to fade, I thought back on things she’d said during the last few months. Frequently she’d been ill, and she clearly felt depressed and unhappy. She said things that weren’t rational, at times. She threatened to leave me, to leave you once you were born. She said she felt as if she were an animal trapped in a cage.”

“She didn’t want me.” I sat down again.