Gianna, a young radio singer, marries Giulio, director of a travel agency. Soon after, they welcome a child. The tranquility of their family life is deeply disturbed by the arrival in Rome of a French tourist, Giselle, who falls madly in love with Giulio. He reciprocates her feelings and becomes her lover. Gianna separates from her husband and devotes her attention to the child, while Giulio begins to live with Giselle. But the thought of his family leads Giulio to ponder severing ties with his lover. Unexpectedly, Giselle's lifeless body is found in Giulio's apartment. Evidence points to Giulio's guilt, so he attempts to escape abroad. Giulio is involved in a car accident close to the border, nearly killing him. In the hospital, it is revealed that Giselle was killed by her former Parisian lover. Healed of his serious wounds, Giulio returns to the affection of his wife and little daughter.