Dario is a little publisher from Milano. He is going to the Mantova Book fair. Marta, his unsatisfied wife, accompanies him. Leon is a French designer-photographer. While Dario is busy with his own business, Marta visits the celebrated Palazzo Te; here under Giulio Romano's fresco representing Jupiter's erected penis she meets Leon. Immediately they become lovers and spend the entire book exhibitions' days making love almost everywhere. This liaison will have soon effects also on the relationship between Marta and Dario.