Thirteen-year-old Evan Hanson is always the last in her family to know what's going on. Her father, Gene, who's been meaner since he began serving in Vietnam, isn't around much, and she likes it better that way. But then her brother, Adam, gets drafted and her anti-war mother, Endura, takes him across the border to Canada, leaving Evan alone with Gene and her younger, special needs brother, Teddy.

When he realizes Endura isn't returning, Gene takes Evan and Teddy to Eat and Get Gas, his mother's cafe and gas station. There, as well as her no-nonsense but loving grandma, Evan encounters Aunt Vivian, a teasing but caring know-it-all; Uncle Frankie, injured in Vietnam and suffering from PTSD; Paco, the draft dodger Frankie is hiding; Hal and Hubert, the strange but gentle next-door neighbors; and Louanne, Frankie's reserved sister. She is drawn in particular to Louanne, who was disfigured by a car accident that killed the rest of her and Frankie's family.

Evan finds a new freedom, and she starts to carve out a place for herself. She eventually, too, learns some of the family secrets she's been kept in the dark about—and comes to understand that her mother isn't coming back any time soon. Then, after reading a letter that wasn't meant for her, Evan discovers the biggest secret of all.