Starring Isabel Ruth and Lima Duarte, Paulo Rocha's film takes place on the shores of River Douro, where an intense story of jealousy, betrayal and mystery takes shape. A couple live in a tense relationship: she is a guard, he runs a boat. Their niece Mélita, saved by António from drowning, makes Carolina jealous. A gypsy fortune-teller, Zé dos Ouros, enters the plot when he tries to sell Mélita a necklace, revealing disturbing visions. Carolina, consumed by jealousy, becomes involved with the gypsy, while António is attracted to his niece.