After a 22 years marriage, a couple shows the signs of a crisis. She thinks he has a lover, and it actually seems so, but does the other woman really exist?

Sixties. A group of kids are in their last year of high school. Renato, a young student, is in love with the beautiful Manuela but she does not reciprocate her feelings. One day Renato, on the occasion of his parents' departure, decides to hold a party at his house to which he invites Manuela and two other companions, but a few days later he ends up being suspended from school after having peeked into the girls' gym. So the protagonist plans to leave for Sweden in search of easy conquests but on the train he meets a beautiful lady who intends to betray her husband. Renato is unaware that she is the wife of one of her professors and the situation gets complicated.