Rose (Annabeth Gish) is the oldest of three sisters and is coming of age in Las Vegas in 1950. Her stepfather Jack (Jon Voight) is home from WWII but suffers from post-traumatic stress and drinks heavily. When he drinks, he gets violent and after several outbursts including one where she slaps Rose hard enough to leave bruises on her face, Rose’s mother (JoBeth Williams) convinces him to go to an inpatient rehab facility. During this time Rose’s favorite Aunt Starr (Ellen Barkin) comes to live with the family while she’s getting a divorce. Starr immediately starts dating and staying out to all hours of the night, which angers Rose’s mother.
Jack returns home sober but starts drinking again fairly quickly, and becomes more and more paranoid about an nuclear bomb test that is scheduled to occur in the coming days. Rose wins the school spelling bee and when she returns home from school, she finds Starr and Jack kissing. When Rose’s mom finds out what happens, she throws Starr out and Rose quietly runs away with the boy next door.
Jack tries to make amends and catches up with Rose in the desert. He makes peace as best he can with her and even finds her lost pair of glasses. Back at home with a new sense of peace among them, they all watch the bomb blast together as a family.