Without career or children after years of marriage to Andrea, an unscrupulous businessman, Gabriella is bored with her life. One morning she is summoned to the assize court to be the only female juror in the trial of Tina, a cleaner, accused of murdering her unemployed husband Gino.
Evidence and flashbacks reveal Tina's side of the story, from first meeting Gino to the night when she saw his body disappear into a sewer. Their relationship emerges as an unpredictable mixture of violent fights, heady sex, and periodic infidelities, yet it is clear she loves him still. Instinctively Gabriella feels Tina cannot be guilty, but cannot help contrasting the earthy vitality of the couple's precarious existence with her own comfortable but anaemic life from which love and sex have faded.
When it seems nothing will save Tina, she mentions a rich lover whose identity she had been protecting and who had been able to see the fight in which Gino fell to his death. From the incomplete description, Gabriella realises that it is her husband Andrea. She tries to make him testify, but he swiftly leaves the country. Just as the jurors reach a verdict of guilty, Gabriella having abstained, a surprise witness appears. It is Gino, alive after all and accusing Tina of abandoning the marital home (a shack beside the sea). The two pick up where they left off, fighting and making love.
