Sal introduces herself, her move from Bybanks, Kentucky, to Euclid, Ohio, her hatred of Mrs. Cadaver, and her new friendship with Phoebe Winterbottom. The first mysterious message appears on the Winterbottom doorstep. The road trip with Gram and Gramps begins.

More messages appear. Phoebe spots the 'lunatic' near her house and becomes convinced he is dangerous. Mrs. Winterbottom grows increasingly unhappy, though no one in the family notices. On the road, Gram and Gramps visit Mount Rushmore and the Badlands.

Mrs. Winterbottom vanishes. Phoebe is frantic, insisting her mother has been kidnapped. Sal helps Phoebe investigate but recognizes, with growing dread, the parallels to her own mother's departure. On the road, Gram's health worsens. Sal tells the story faster, as if finishing it will hold something together.

Phoebe and Sal track down the lunatic. He is Mike Bickle, Mrs. Winterbottom's son from before her marriage — given up for adoption and now searching for his birth mother. Mrs. Winterbottom returns with Mike and introduces him to the family. Phoebe must reconfigure everything she believed.

Gram suffers a fatal stroke at a motel in Coeur d'Alene, Idaho. Gramps drives Sal to Lewiston anyway. Sal walks down to the site of the bus crash where her mother died. She touches the earth. She understands, finally, that Sugar left not because she did not love Sal but because grief had broken something in her that only distance could address.

Sal returns to Bybanks with her father, who has bought back the farm. She accepts Mrs. Cadaver. She visits her mother's sugar maple tree. She begins to live inside her grief rather than running from it. The novel closes with Sal on the porch, listening to the singing tree, understanding that home is not a place you return to unchanged but a place where you bring everything you have learned.