Gilbert Grape is a small-town young man with a lot of responsibility. Chief among his concerns are his mother, who is so overweight that she can't leave the house, and his mentally impaired younger brother, Arnie, who has a knack for finding trouble. Settled into a job at a grocery store and an ongoing affair with local woman Betty Carver, Gilbert finally has his life shaken up by the free-spirited Becky.
Eliza D'Amico thinks her marriage to Louis is going great until she finds a mysterious love note to her husband. Concerned, she goes to her mother for advice. Eliza, her parents, her sister Jo, and Jo's boyfriend all pile into a station wagon to go to the city to confront Louis with the letter. On the way, the five explore their relations with each other and meet many interesting people.
While on a family vacation, rafting expert Gail takes on a pair of armed killers while navigating a spectacularly violent river.