David Hastings, a man in his seventies with progressive dementia, flies on a private jet toward London with his young assistant, Cody. The plane belongs to Bill Stearns, David's longtime friend and former colleague, who has lent it as a farewell gesture. London is only a stopover; David's true destination is Zurich, Switzerland, where he has arranged to end his life through the country's legal assisted suicide program.
David's consciousness drifts throughout the flight. He plays solitaire, drinks Scotch despite medical advice, and clutches a small leather notebook filled with essential reminders in shaky handwriting, including the words "ROSE CHAIR APPLE" from a failed cognitive test and his daughter's name and address. His liaison at the Swiss organization is a woman named Anna Gould, whom he privately calls "Ghoul." The months-long process has required medical assessments and a letter explaining his decision that Cody had to compose because David could no longer write coherently. David is aware that Cody has been quietly taking money from him, perhaps nearing six figures, but he views this as fair compensation for Cody's loyalty. Cody holds power of attorney, and David's estate is organized so that a lawyer will handle the will after his death.
After landing at London City Airport, David settles into a grand hotel. He recalls his ex-wife, Annabel, and their honeymoon in London when they were barely in their twenties. He remembers the onset of his illness: the enormous energy spent concealing cognitive lapses, and the moment at work when a budget error of nearly eight figures exposed his decline. Stearns defended him and offered a lesser position, but even that failed. Clinical testing confirmed his diagnosis, including the moment a doctor asked him to remember three words and David could recall only one. No medication could improve his condition. Unable to arrange assisted suicide in California, David chose Switzerland, noting with dark humor that the cost is less than hiring "two and a half hitmen" (68).
At the hotel, David wanders to the indoor pool, sits on the edge with his feet in the water while still wearing his coat, and tells two women he is waiting for his wife, briefly confusing the present with a memory of Annabel, before Cody escorts him upstairs.
That evening, David dines at a private club with his daughter, Rebecca, who lives in London with her English husband, Geoff, and their nine-year-old son, Rainer. David tells her the Zurich trip is a consulting project for Stearns; she brightens at the idea, unaware he has kept his diagnosis entirely from her. He struggles with the menu, eats with his fingers when she tries to cut his meat, and loses track of time. He reflects on the email Cody will send Rebecca after his death, informing her that he has "passed peacefully and legally in Switzerland" (107) and expressing the love he cannot articulate in person.
That night, David meets a young woman named Radha at the hotel bar and brings her to his room. He tells her he is going to die soon; she responds casually, entirely missing his literal meaning. He confides that he wants to find an old friend named Tom and apologize for unkindnesses committed in high school.
The next day, David and Cody visit a museum and then go to Rebecca's house. Rainer opens the door, a blond, slight boy whose appearance reminds David of Tom. In Rainer's room, a model train set fills a table, and when Rainer turns it on, miniature streetlights flicker to life. David is overcome with emotion at the intricate world. Rainer plays Mahler's Ninth Symphony on his phone, calling it "the farewell symphony" (166), but when the music swells into frightening urgency, David asks him to stop. David tells Rebecca he loves her, twice, embarrassing them both, and leaves her in the doorway.
On the drive back, David realizes his phone is missing and insists they return. Rebecca opens the door reluctantly. A woman named Lauren, a guest of Rebecca's, appears in the hallway, and the sitting room shows signs of an interrupted evening: two wineglasses, a wine bottle dripping on the rug. David briefly senses some private truth in the murmur between the two women, though the recognition passes before he can hold it.
David and Cody fly to Zurich, where the old-fashioned hotel has a caged elevator and a heavy room key. The next day, David meets Ghoul at a riverside café, where she asks why assisted suicide is the right decision. David explains the feeling of entering a room and finding no answers, the regions of his brain switching off one by one. Ghoul tells him it is much worse when people come too late. David buys a first edition of
Twenty Thousand Leagues Under the Sea at a bookshop, deciding to bring it to Tom and finding meaning in the title's reference to distance. That evening, Stearns calls to say goodbye, telling David he is brave and that he loves him.
Alone afterward, David's memories turn to the central trauma of his life. During summers at Tom's family's lake house, where the house ran on kerosene lamps, David was close to happiness. One afternoon on the dock, Tom's finger grazed David's wrist, and what followed happened without words: They kissed. That final summer, David drank himself into a stupor hoping it would happen again, but Tom turned him away. In their final year as roommates, the air between them soured. When Tom was announced as class speaker, a group of boys planned a nighttime abduction: They pulled a pillowcase over his head, drove him into the woods, and fired a gun into the trees. Tom, in terror, soiled himself. The boys left him alone in the dark. David, asked beforehand what he thought, had done nothing to stop it. No one was ever punished. At graduation, Tom's mother told David he had been a good friend, words he would turn over for the rest of his life, uncertain whether they were sincere or accusatory.
Cody reveals that Tom and his wife never confirmed the visit, but David insists they go. They drive across the French border to a stone house with a red door. Tom's American wife says he is not available, and David grows agitated, trying to push past her. She screams, and Cody pulls him back. After an hour, Tom arrives home and agrees to sit in the car. David says he is sorry. Tom deflects, saying he barely remembers that time. David asks about Tom's sister, and Tom reveals she has died, that life was tough on her. David pushes further, trying to communicate that he loved Tom once. Tom says he cannot give David what he is looking for and returns to the house. Cody drops the book through Tom's mail slot.
On David's final evening, he dines at a Zurich restaurant, then finds Cody at the hotel bar with his partner, Sam. Agitated over a sweater he believes is his, David accuses them of going through his things. Upstairs, he clings to Cody for comfort. Unable to sleep, he walks alone to the river, where swans drift under a bridge.
On the final morning, David wakes before dawn and makes his bed, a gesture toward his father's old advice. In the elevator, he asks Cody's age; Cody says he is almost 34, and David recognizes the boy has a long runway ahead. At six, the car arrives at an industrial park. The room has high windows, a hospital bed with a yellow sheet, and a poster of a nebula. David signs the paperwork while a video camera records. Ghoul reminds him he can stop at any time. He takes anti-nausea pills, starting a 40-minute clock, and surprises himself by taking Cody's hand. When the time passes, he asks for another round instead of the barbiturate, buying himself one more stretch.
His consciousness shifts. He catalogs his life: the hidden things, the fits of bravery. He regrets not having a family member present and thinks of Annabel, who knew him before their lives happened to them. Then David takes the barbiturate, bitter, mixed into water, and drinks it in shuddering parts. He feels an undertow deeper than any he has known and does not resist it. Tears run down his face, but they are not from sadness. His final thought is broadcast into the air: "I am holding out my hand" (336).