[1][2][3] The upper class couple Stefano and Giovanna spend the summer in their little house on Lake Como.

He lets the couple spend the night in his house and makes hints that he would be interested in a partner swap.

While reading the box number ads in the newspaper, she suddenly discovered something that she suspected Stefano was behind.

When the second couple comes to visit, Stefano takes a liking to the woman, but Giovanna finds the man pushy.

An unexpected opportunity arises later when they let their friends Diego and Gabriella show them a large palazzo.

He doesn't want to know anything about swapping partners; Distraught, he asks her to confirm under an oath that nothing has happened that night.