Jeanne Brigitte Bardot arrives at a funeral service to visit her cousin Paul Mathieu Carrière, a priest. As Paul prays, he spots Jeanne. When the funeral ends, the two reconnect after a year apart, and Jeanne confesses she has killed someone. Back at her residence, Jeanne talks with Léporella Michèle Sand, her secretary, about inheriting her father's wealth after he died of a heart attack. She believes she is the reincarnation of Don Juan and prides herself on destroying men who fall for her charm. Shortly after, Léporella leaves and Paul arrives. He questions Jeanne's claim that she murdered someone, and she recounts the tale.
At an archery competition, Jeanne and Paul watch Pierre Gonzague Maurice Ronet win the championship. Pierre drives Jeanne home; as a married man, he admits adulterous affairs. They begin an affair, but he leaves while she is bathing. A week later, at a dinner invited by Pierre's wife, with a playwright and his girlfriend present, the scene thickens. Three months later, she sees Pierre outside as he leaves his workplace. At Pierre's residence, Jeanne confesses her love, but he declines to continue the affair.
Angered by the rejection, Jeanne schemes to trap Pierre in a public scandal by luring him to a secluded mansion on an island near Sweden. The two exchange a tense encounter, but days later they attend a university party. During an orgy, a female blonde student is struck, and Pierre is photographed helping the student, which becomes a front-page French press story. The scandal leads to a political uproar, and Pierre's wife chooses to divorce him.
Back in France, Pierre finds himself nearly destitute. He enters a bar where he spots Jeanne and blames her for ruining him. Jeanne then rides with Louis Prévost Robert Hossein and his wife Clara Jane Birkin. Louis hosts a party at his suite that night; Clara explains to Jeanne that Louis is a savage. Enraged, Louis tosses Clara into an interior pool, leaving Clara to hurry upstairs. Later, Jeanne accepts an invitation to London with Louis and Clara, and the train ride offers a chance for Jeanne and Clara to form a romantic bond.
In London, Louis discovers Jeanne and Clara in bed together, hoping for a ménage à trois. The two women walk for a bit instead, while Louis orders them to stay put. Jeanne bluntly tells Louis she was never interested in him, but only wanted to possess him through Clara. Anger drives Louis to slap her repeatedly. Paul contemplates leaving, but discovers Jeanne has locked the door from the inside. He tries to leave, but Jeanne keeps him inside as she continues her story.
Jeanne then recalls her relationship with the guitarist Robert Walker Jr., spotted at Louis's party. After the nightclub closes, the guitarist serenades Jeanne; she asks if he would give up everything for her. He agrees, and the two consummate, only for the guitarist to slit his wrists with broken glass. Jeanne calls an ambulance, but the guitarist dies.
Jeanne finally confesses her guilt, and she and Paul have sex. She meets with Léporella again and spots Pierre outside, arranging to meet with him the next day. Before Jeanne arrives, Pierre doses the floor with gasoline and lights a fire. Pierre escapes, but Jeanne is burnt alive in the blaze.
