A group of four teenage girls in the San Fernando Valley during the late 1970s have the usual problems with life. Deirdre (Kandice Stroh) is a disco queen who is fascinated by her sexuality, likes boys and has many relationship troubles. Madge (Marilyn Kagan) is unhappily overweight and angry that she is still a virgin. Her parents are overprotective, and she has an annoying younger sister. Annie (Cherie Currie) is a teenage runaway who drinks, uses drugs, and runs away from her abusive father, a policeman. Jeanie (Jodie Foster) feels she has to take care of them all, is fighting with her divorced mother, and is yearning for a closer relationship with her distant father, a tour manager for the rock band Angel.
The girls believe school is a waste of time, their boyfriends are immature, and that they are alienated from the adults in their lives. All four seem immersed in the decadence of the late 1970s. (The adults in the film seem to be caught up in the craziness of the era as well.) The only way for them to loosen up and forget the bad things happening in their lives is to party and have fun. Annie is the least responsible, while Jeanie is ready to grow up and wants to stop acting like a child. Jeanie is most worried about Annie and continually takes risks to try to keep Annie clean and safe. Annie's unstable behavior keeps everyone on edge, and finally leads to her death in a car accident.
Annie's death brings changes for the rest of the girls. Madge marries Jay (Randy Quaid), an older man who deflowered her, Deirdre no longer acts boy-crazy, and Jeanie graduates from high school and is about to head off to college. After Madge and Jay's wedding, Jeanie visits Annie's grave and smokes a cigarette. With a smile, she muses that Annie wanted to be buried under a pear tree, "not in a box or anything", so that each year her friends could come by, have a pear and say, "Annie's tastin' good this year, huh?".