Giuliano and Nora, bourgeois siblings of Milan, are spending their holidays in the comfortable family villa in Vulcano, Eolie. With them there are friends Barbara, Giuliano's fiancée, and Daniele, a young man who, apart from the usual rites, has no sexual experiences and is also shy. While Nora, after waiting in vain for Daniele to come forward, so she decides to leave them and follow other friends on the cruise, Giuliano remains faithful to Barbara until she meets nudist Trella, a young Norwegian woman who is sailing with her husband, Bjorn. The situation becomes tense when middle aged Adriana, Giuliano and Nora's mother's friend arrives at the villa. Her sentimental relationship is in crisis. She little by little puts things right.