The couple Alfredo and Susanna are two well-off fifty-year-olds who lead a stimulating cultural life. He is an architect and she is a psychologist; they live in Rome but spend their weekends at their country home in Umbria, where they love to spend their days walking in the forests or relaxing poolside with a good book. One day, as she goes into town, Susanna sees a girl prostituting herself in the bushes on the side of the road and decides to save her from her unhappy existence, despite the enormous differences that separate their ways of life.