Ambrogio Carugati, a perpetually failing graduate student, turns to a former university classmate, the gynecologist Roberto Setti, to escape the arranged marriage with Gabriella, a girl he doesn't like.

Tina, an old lady and detective stories buff, moves to town in the house of a god-daughter of hers whose husband is a private dick. She thinks she will be able to help him with his inquests. He does not agree with her and tries to discourage her by any possible means.