At her Los Angeles, California, home, Helene Bradley hosts an all-women birthday party for herself and friends Sadie and Kate. Helene is celebrating her fortieth birthday, Sadie is about to turn fifty, and Kate recently reached thirty. Martine, a French filmmaker staying at the house, decides to shoot the party for a television documentary. She begins by turning the camera on herself and asking, “Do you have any problem with food?” Helene deals herself a hand of Tarot cards to see what her fortieth year has in store for her. She asks her stepdaughter, Lydia, if Frank, Lydia’s father and Helene’s husband, always runs away on birthdays. Soon afterward, Frank calls to assure Helene he will home by 7:00 that evening. Other women, including Kate, Sophie, Sadie, and Sadie’s daughter, Jennifer, arrive. Seeing Martine wearing a bikini bottom beside the swimming pool, Sophie compliments her beautiful body, but confides that Helene Bradley has a poor body image of herself. Sadie, a theatrical agent, complains about being tired of fighting the effects of aging. She has a thirty-four year-old boyfriend, but feels jealous, especially when daughter Jennifer is around. When Helene’s mother, Mrs. Whitney Williams, arrives to drop something off, Helene begs her to stay for the party. Sophie compliments Kate on her twelve-year marriage, adding that she could not live or have sex with anyone that long. As other women arrive with presents, they discuss food, sex, and their bodies. Jennifer admits she loves food, but is self-conscious about eating in front of others. “It’s like sex,” she says. Lydia tells Martine that she was nine when her father married Helene, but she has always maintained a good relationship with him and her stepmother. Martine replies that her father was always distant. When Helene’s younger sister, Nancy, arrives, Helene begs her not to dominate their mother’s time at the party. Lydia tells Whitney, her step-grandmother, that she feels self-conscious about eating Frank and Helene’s food because it implies an acceptance of their beliefs. Sophie gives Helene two “batacas”—padded bats—for a birthday present and demonstrates how to use them to “get out your rage.” They hit each other with the harmless bats, screaming, “I hate you!” Jennifer begs her agent mother, Sadie, to get her an acting job, but Sadie does not want her to be an actress. As the oldest, most serene woman at the party, Whitney attracts the others’ needs to confess their insecurities. Most of the guests think they are too fat. Whitney expresses confusion about why attractive, successful women are so insecure about their ages, their bodies, and “all this food business.” Whitney asks daughter Nancy why a woman would eat and vomit, especially since Nancy’s husband is so successful. However, Nancy claims she always had a weight problem, whereas Helene was always thin. Sophie eats her own macrobiotic meal because she hates the greasy, “horrible food” Helene serves. She expresses her concern to Whitney about Helene’s “horrible, horrible husband.” Whitney responds that Sophie is too negative about everything. When Whitney compliments Martine on being the envy of other women at the party, the French photographer confides her lifelong insecurity about being “too big,” and wishes she were more “delicate” instead of “big-hipped and perfect for having babies.” Whitney recalls that when she was young, she worked as a “personality model,” not a fashion model, because she enjoyed being “normal weight.” Two guests arrive and present Helene with “screaming cups,” open-ended half balls with foam interiors for muffling sound. The women laugh as they scream into them at the top of their lungs. When Jennifer complains to Sophie that her mother refuses to represent her as an actress, Sophie replies, “Your mother hates you!” Milly sits down with Dr. Penson, a plastic surgeon, to discuss her many unsatisfying “breast enhancements,” and wonders if a facelift might offset the problem. Jennifer tells Lydia that her mother’s younger boyfriend keeps looking at her, and sometimes sneaks her food. She feels guilty because that morning she revealed to him that the party was a celebration for her mother’s fiftieth birthday, an age considerably greater than Sadie had revealed to him. Jackie, one of Sadie’s clients, whispers to another client, Eloise, that she is leaving for a bigger agent, but does not know how to break the news. Eloise begs Jackie to “take me with you.” Kate and Martine discuss abortions they had when they were younger, and Martine regrets being beyond marriage or having babies. When the three-dozen women gather for cutting three birthday cakes, the first piece of cake is passed from hand to hand, but nobody eats it. Whitney enjoys her own piece of cake and exclaims how good it tastes. Sadie catches daughter Jennifer eating a large piece of cake alone and lectures her on staying thin if she hopes to find a good husband. Sophie slips into an empty room to telephone her psychiatrist, because she is having a hard time keeping herself together. Afterward, she chants and calms herself with the excuse that “it’s only a group of women” she is dealing with. Martine begins filming women talking about their relationships with food. One admits she is “at the mercy of food.” Others reveal how in childhood food became a substitute for love, or an escape from emotional pain. One claims she is looking for a man who excites her as much as “a baked potato.” Helene explains that food has replaced sex for many women, and confesses she recently woke up in the middle of the night eating ice cream. When Frank telephones Helene that he will not be home as promised, she is crushed. Helene confesses to her mother that Frank has been spending more time away. Hearing Helene’s lament, Sophie tells her Frank is having an affair, everyone else at the party is aware of it, and according to gossip the other woman is a brunette attending the party. Sophie suggests Helene “get in touch” with her rage, and Helene goes into the kitchen and cries as she eats a piece of cake. Whitney tells her daughter that familiarity naturally breeds contempt, but women must “carry on,” accept an occasional infidelity, and keep the marriage intact until the husband returns. Sophie quizzes Martine about her “relationship” with Frank. One guest confesses she had an affair with Frank in college, but that was fifteen years ago. In front of all the guests, Whitney sings “The Way You Look Tonight” to Helene as a birthday present. Sophie finds Jennifer ravenously eating cake in the bathroom. The young woman confesses she is striking back at her mother, who wants her to be thin. Caterers serve the main meal, and the women eat as they talk to Martine’s camera. When Helene telephones Frank and discovers he is not where he is supposed to be, he confesses the truth about his affair. Later, Helene cries as she tells Nancy that Frank is not coming home. Unable to deal with her sister’s pain, Nancy hurries away and gets Kate, but when Kate tries to commiserate, Helene accuses her of being Frank’s lover. Asked where she got that idea, Helene blames Sophie. Kate searches for Sophie and finds her vomiting in the bathroom. Sophie cowers as Kate screams at her, then confesses her jealousy over Kate’s successful marriage and “perfect life.” Later, as the party breaks up, Helene feels more accepting of, even relieved by, her new status as a woman alone. “It’s scary, but exciting,” she declares. Martine replies that unlike Helene, she has always been alone, but now feels ready to enjoy a more permanent relationship.