It's 1967 and fifteen-year-old Joanne's San Francisco neighborhood of Haight-Ashbury has become inundated with hippies for the "Summer of Love," which thrills her but appalls the rest of her family. In the midst of preparations for her sister's wedding, Joanne meets Martin, an enigmatic and irresistible hippie, and begins to see him secretly. Over the course of the next year, Joanne discovers a world of drugs, antiwar demonstrations, and psychedelic dances that both fascinates and frightens her. As this world collides with her family's values, Joanne must decide whether to stay with her middle-class family and pursue her love of classical music or follow free-spirited Martin into a new kind of life.