Chicco, Massimo, and Bruno Sacchi are on vacation in Tropea with Sharon Zampetti. Due to an agency error, the Zampetti family and the Sacchi family (Bruno's), find themselves renting the same house. Unable to change, they mutually decide to vacation together. Bruno also invites his other friends. Over the course of the summer, the kids become rivals to a young nobleman, Prince Leopoldo, with whom Sharon has fallen madly in love. But eventually, the kids discover that the Prince is penniless and only wanted to marry Sharon for money.