Armando Ponziani is the owner of a chemical factory and lives with his wife Ersilia and their son Franco in a villa on Lake Como. Ersilia, aware of her husband's unfaithful tendencies, has imposed that only women who are not considered attractive work in the company. However, she is unaware that Armando is having an affair with a Swedish mistress named Ingrid, who is kept in a hotel in town.
One day, Armando and Ersilia are involved in a car accident, during which their secretary mysteriously disappears. Dr. Mingozzi, who aspires to become director of the Ponziani company, proposes to have his fiancée Luisa work as his new secretary. Because of her extraordinary beauty, Luisa becomes the object of interest of both Armando and Franco, the couple's son.
Eventually, Luisa falls in love with and marries Franco, and orchestrates a situation in which Ersilia enters into a relationship with Oscar, a friend of Franco. This allows Armando to continue his relationship with Ingrid unhindered.