Florence "Flo" Greene, a 92-year-old widow, has received a terminal cancer diagnosis. Given roughly a month to six weeks to live, she sits at her kitchen table with floral stationery and begins writing a long letter to Ruth "Ruthie" Eimers, a woman who grew up next door and with whom Flo has maintained an honest, soul-baring friendship since Ruthie's childhood. Flo intends to leave Ruthie her house and everything in it, and the letter will serve as both a guide to those possessions and a record of the memories they hold. She hints at a long-held secret buried in her backyard behind the roses, which she promises to reveal. She also knows Ruthie is planning to divorce her husband, Jonathan, and hopes her stories might change Ruthie's mind.
The novel unfolds in two intertwined strands. One is Flo's letter, in which she moves from object to object through her house, each item prompting a story about her marriage to Terrence, her memories of young Ruthie, or her reflections on love, forgiveness, and loss. The other follows Flo's present-day life during her final weeks, as new friendships give her remaining time unexpected richness.
The present-day narrative begins when Teresa McNair, a neighbor Flo has noticed but never met, appears at her door asking for help catching an escaped cat. A friendship quickly forms. When Flo discloses her diagnosis, Teresa reveals she is a death doula, someone who helps people transition from life to death. She tells Flo about a terminally ill gardener who left hospice, returned home, and lived two more years before dying peacefully. Teresa takes Flo's hands and asks her to close her eyes and imagine healing. Flo feels a rush of sensation, though she remains uncertain whether the mind can cure the body at her age.
Over repeated porch visits, Teresa confesses she has always driven men away before they could reject her. She reveals that as a college freshman, a devastating breakup led her to gather aspirin with the intention of ending her life, though she ended up buying an entire pizza instead, and things gradually improved. Flo, seeing someone who deserves more, visits the library to ask the librarian, Mimi, about online dating sites.
Flo's letter grows steadily. She writes about her pearls, a Christmas gift Terrence gave her to remind her what she was worth. She recalls a fight resolved by going out for hamburgers, during which Terrence bought her a plastic toothpick dispenser she had admired, getting down on one knee to present it. She describes his phone proposal, too shy to ask in person, and the modest ring he brought to her backyard. She tells Ruthie about mismatched silver spoons that young Ruthie once arranged with exacting precision the day before leaving for college, crying because she wanted things to be perfect. Flo told her then that part of life was learning how perfect imperfect could be. She confides that she always wished she were Ruthie's mother; she and Terrence wanted children badly, but it never happened, and after Terrence quietly said it was not for them, they never spoke of it again.
In one of the letter's central passages, Flo describes a rubber band kept in a small white box with a red ribbon in her kitchen drawer. Early in their marriage, when Flo feared their love would break, Terrence pulled out a rubber band, stretched it to its limit, and released it. He told her they would always do the same: No matter what happened, they would return to their original shape, which was love. She placed the rubber band in the box, and whenever trouble came between them, she looked at it and trust returned.
In the present, Flo gives Teresa the dating information. Teresa resists but admits she has already been on a date with Jim, a cashier at her grocery store. When Flo asks Teresa to describe her deepest romantic fantasy, Teresa envisions being driven into the night to gaze at the sky while someone declares its vastness is needed to hold his feelings for her. Flo urges her to reverse the fantasy and do this for Jim. The next morning, Teresa calls, jubilant: She took Jim to see the stars, and it went well. Soon she brings Jim to meet Flo, and Flo watches him take Teresa's hand and Teresa squeeze back.
Flo's world expands in other ways. She visits her neighbor Mildred Curtis, a former actress in her 80s who recently ice-skated on a frozen lake at one in the morning. Inspired, Flo goes to a salon for the first time, getting alternating colors on her toenails and a streak of turquoise in her hair. She arranges a tea where Teresa, Mildred, and Mimi meet, feeling satisfaction knowing these women will have each other when she is gone.
Flo's health declines. She wakes from a nightmare about the devil and calms herself with Terrence's old advice: Imagine the devil in diapers. She experiences a frightening episode where all color drains from her vision, and another where her breathing goes ragged and pain seizes her before subsiding. Each time, she resolves to finish the letter.
At last, Flo reaches the secret she has been circling. Years into her marriage, she found half a dollar bill hidden in Terrence's jewelry box; he refused to explain. Years later, a letter arrived from Paris containing the other half and a note: "For so many years I have waited for nothing. Au revoir." Flo confronted Terrence, who confessed everything. During the liberation of Paris at the end of World War II, a French woman named Simone rushed from the celebrating crowd and kissed him. Despite being newly married to Flo, Terrence spent three days with Simone, and they had a son, Jean-Claude.
Flo was devastated but held to the vow she made when Terrence left for war: Nothing would make them part. She forgave him. After Terrence discarded Simone's letter, Flo retrieved it and wrote to Simone, asking for a photograph of Jean-Claude and explaining that she could not have children and wanted to see what Terrence's son looked like. Simone sent a photo of a handsome young man with Terrence's eyes and dimples. The two women exchanged many letters, forming a kind of friendship, before gradually stopping. Flo buried the correspondence in a rosewood music box behind the roses, unable to keep it in the house but unable to throw it away. This is what Ruthie nearly discovered years ago.
Flo uses this story to argue her case directly. She tells Ruthie to think hard before divorcing Jonathan, insisting her complaints have assumed outsized importance. She declares forgiveness "our holiest sacrament" and relays what Teresa taught her: The three most common things people say on their deathbeds are "I forgive you," "I hope you forgive me," and "I love you."
On what appears to be her final morning, Flo can barely see. She dresses in what is likely the tweed suit she wanted to be buried in and makes her way downstairs to finish writing. She catalogs what she will miss: hot cross buns at Easter, flowers bowing in gardens, snow like falling lace. The letter breaks off mid-sentence.
A framing letter from Teresa, placed at the novel's opening, has already revealed the outcome: Flo was found at her kitchen table, dressed and ready, the letter unmailed. Teresa sent it to Ruthie as Flo had asked. Ruthie's response closes the main narrative. She requests a few cherished items, including the silver spoons, the pearls, and the white box with the rubber band, and returns Flo's letter to Teresa so Teresa can read it. Ruthie and Jonathan are buying a new house in California together, indicating she has chosen not to divorce.
In a brief epilogue, a young pregnant couple buys Flo's house. The wife notices Terrence's accidental footprint in the concrete by the cellar door and insists on keeping it, though she cannot explain why. On a later day, a mother and her small son stop at a table outside the house marked FREE, piled with Flo's remaining things. The boy takes a bowl of rocks, the ones Ruthie once gave Flo as "magic beans," declaring them special. That night, the new wife finishes reading Flo's letter, which Teresa passed along before moving away to marry Jim. Overcome with love for her sleeping husband, she tucks the letter beneath tiny baby shirts in the nursery drawer. In the novel's final image, birds gather in water pooled in Terrence's footprint, bathing and shaking off droplets that capture light before they fall and disappear.