The novel opens with a prologue narrated by the house itself at Seven Sunset Lane in Beaufort, North Carolina, built by shipbuilders in 1769. The house recalls its happiest years with Becks and Townsend Saint James and their children, Lon and Virginia, and reveals that no one has lived inside it since the couple "unexpectedly met their demise" on August 28, 1976.
The story alternates between two timelines. In the present day, 33-year-old Keaton Smith, a marketing coordinator at the lifestyle brand All Welcome, expects a promotion but instead learns her boss and mentor, Allison, is pregnant by Jonathan, the head of HR, who is both Allison's ex-husband and Keaton's recent ex-boyfriend. When Keaton lashes out, Allison fires her without severance. Jobless and without a home, Keaton learns that her mother, Virginia, and uncle, Lon, still own the Beaufort house where they grew up but have never returned since their parents died. They ask Keaton to clean it out and prepare it for sale, offering her a 20 percent commission. Keaton agrees and drives south with her mini Goldendoodle, Salt.
The house is a perfectly preserved time capsule from 1976. Keaton has never even seen a photograph of her grandparents. Salt retrieves a white leather notebook, "Rebecca Saint James's Guide to Entertaining," containing Becks's recipes, guest lists, and tips written to Virginia. An older neighbor, Violet Scott, recognizes Keaton as Becks's spitting image and mentions that Becks and Townsend "disappeared," contradicting the car-crash story Keaton has always been told. Keaton also meets Anderson, the 10-year-old son of her next-door neighbor, Bowen. Anderson's mother, Kerry, left when he was a baby. Bowen is initially cold, but Anderson quickly becomes Keaton's devoted helper.
In the 1976 timeline, Becks is a legendary hostess whose weekly summer suppers are Beaufort's social highlight, built around guest lists where all 12 guests share an unspoken common thread. Her doctor and dear friend, Daniel Walker, delivers a devastating diagnosis: advanced pancreatic cancer with roughly six months to live. Becks refuses to tell Townsend, wanting to protect their remaining time. She drives to visit her estranged mother, Myra, from whom she has been cut off for 41 years. Myra, a Methodist minister's widow, blamed Becks for her father's death: Reverend Bonner had a fatal heart attack upon learning Becks was engaged to Townsend, a Catholic. The visit fails; Myra orders Becks to leave.
Townsend's earliest journal entry, from 1935, recounts meeting Becks on the beach and falling instantly in love. Their interfaith romance caused both families pain, but Becks fought for the relationship, declaring at Townsend's office that she chose him over her family. They married at St. Paul's Episcopal Church in Beaufort, finding the Episcopal faith as a bridge between their backgrounds. During World War II, Becks won over Beaufort's women by hosting dinner parties while Townsend served as a pilot, turning strangers into lifelong friends.
In the present, Keaton settles into Beaufort life, attending morning coffee with the Dockhouse Dames, four older women whose mothers were Becks's close friends. The Dames reveal that after the last dinner party, Becks and Townsend's convertible was found submerged in Taylor Creek, but their bodies were never found. Keaton starts cooking from Becks's recipes and agrees to put the house on the Old Homes Tour, the town's biggest annual fundraiser, an event Becks herself founded. She and Bowen grow closer, sharing a first kiss on a boat date. Dr. Scott, Violet's husband, tells Keaton that Becks had pancreatic cancer, information her mother apparently never knew. Keaton admits for the first time that she suspects her grandparents' death was not an accident.
In 1976, Becks notices Townsend's worsening memory. A new neighbor, Peter, moves in next door. Becks recognizes his ice-blue eyes and bat-shaped scar from a description Virginia once gave of a doctor who allegedly killed a patient. When Becks confronts him, Peter explains the patient was terminally ill and begging to die. Becks initially fears him but comes to a more complex understanding and recruits him for a crucial task: sinking Townsend's convertible in Taylor Creek to stage a diversion, paying him with cash hidden in hollowed-out books.
Keaton's brother, Harris, a celebrity PR executive, flies down for the Old Homes Tour. He and Anderson discover personally inscribed Hemingway books in the library. Harris reads Townsend's later journals and finds an entry revealing Townsend knew Becks was dying and had been diagnosed with Alzheimer's; he wished they could go together. After the tour, Keaton misinterprets a moment between Bowen and the returning Kerry as romantic and flees to New York. Having already received a job offer when Allison visited Beaufort, Keaton negotiates her return to All Welcome as VP of Operations, securing mostly remote work and an agreement to publish a book based on Becks's notebook. Bowen and Anderson fly to New York, where Bowen explains he has moved on from Kerry and is in love with Keaton. They reconcile.
Virginia finally visits the house, finding hidden cash in hollowed-out books, gold in a secret credenza drawer, and the last of Townsend's journals, which confirms his Alzheimer's diagnosis and his knowledge of Becks's cancer. She opens a sealed letter from Becks expressing pride in her life and telling Virginia that standing in the shadows so her daughter could shine was enough.
The 1976 timeline reaches its climax on August 28, Becks's birthday and the night of her final summer supper. Before the party, she asks Charles, her chief waiter of nearly 30 years, to become Townsend's full-time companion after she is gone. During the evening, her estranged mother Myra appears and reveals that Reverend Bonner, on his deathbed, admitted he was wrong to oppose the marriage, granting Becks the forgiveness she sought for decades. After the guests leave, Becks tells Townsend she is dying. He reveals he already knows and confesses his own Alzheimer's diagnosis. They have each been protecting the other. They agree to end their lives together. Becks removes her engagement ring and flies them to their most cherished place, where the sky meets the sea, then kills the engine.
In the present, Virginia recognizes that a poem Townsend left on the kitchen notepad, a quatrain about "where the sea meets the sky" that they wrote together when she was a child, was a message telling her where they went. She also realizes that Dr. Scott, Violet's husband, is Peter, the man she suspected of murdering her parents for decades, and apologizes to him. The family does not need to tell Virginia the plane is missing from the hangar. She already knows.
One year later, Keaton narrates from the renovated house, which the family decided not to sell. She has published
Rebecca Saint James's Guide to Entertaining, built an Instagram following, and left All Welcome. A search-and-rescue team located the plane, giving the family closure. Keaton and Virginia got their pilot's licenses together, and Keaton's lifelong fear of flying has vanished. Bowen proposes during a dinner party, and Anderson tells Keaton he does not want to call her his stepmom, just his mom, because he chooses her as his family.