One late summer evening in the post-industrial town of East Gladness, Connecticut, nineteen-year-old Hai stands on the edge of a bridge in pelting rain, ready to jump, when he hears someone shout across the river. The voice belongs to Grazina, an elderly widow succumbing to dementia, who convinces him to take another path. Bereft and out of options, he quickly becomes her caretaker. Over the course of the year, the unlikely pair develops a life-altering bond, one built on empathy, spiritual reckoning, and heartbreak.

Isabel Gibson has all but perfected the art of forgetting. She’s a New Yorker now, with nothing left to tie her to Brinkley’s Island, Maine. Her parents are gone, the family bookstore is all but bankrupt, and her sister, Sophie, will probably never speak to her again. But when a mysterious letter arrives in her mailbox, Isabel feels herself drawn to the past. After years of fighting for her independence, she dreads the thought of going back to the island.

Bonny Blankenship's most treasured memories are of idyllic summers spent in Watersend, South Carolina, with her best friend, Lainey McKay. Now in her early 50s, Bonny is desperate to clear her head after a tragic mistake threatens her career as an emergency room doctor, and her marriage crumbles around her. With her troubled teenage daughter, Piper, in tow, she goes back to the beloved river house, where she is soon joined by Lainey and her two young children.

At forty, Peter, an asylum lawyer in New York City, is overworked and isolated. He spends his days immersed in the struggles of immigrants only to return to an empty apartment and occasional hook-ups with a man who wants more than Peter can give. But when the asylum case of a young gay man pierces Peter's numbness, the event that he has avoided for twenty years returns to haunt him. Ann, his mother, who runs a women's retreat center she founded after leaving his father, is wounded by the estrangement from Peter but cherishes the world she has built.

2016: Thirty-four-year-old Mari Starwood is still grieving after her mother’s death as she travels to the storied island of Martha’s Vineyard, off the coast of Massachusetts. She’s come all the way from California with nothing but a name on a piece of paper: Elizabeth Devereaux, the famous but reclusive Vineyard painter. When Mari makes it to Mrs. Devereaux’s stunning waterfront farm under the guise of taking a painting class with her, Mrs. Devereaux begins to tell her the story of the Smith sisters, who once lived there.