Antonio (Ugo Tognazzi) is a 39 year-old father travelling on a highway one summer in his sports car when he sees a broken-down car with a group of teenagers He stops to help them . At first, he thinks of leaving to continue his trip but then notices the beauty of Francesca (Catherine Spaak), a young girl. He decides to remain with the group to try to seduce the girl, despite the difference in age