Blum and Elza conduct Scientific and anthropological researches in a desert island, where they use as subjects a old fisherman, the house keeper and a prostitute from the country. But the affection grows between the three of them, and this feelings are capable of compromising the whole research.

Clementino is a postman who doesn't have much talent for the job and is six months behind in the payment of his apartment. While delivering a correspondence, he is kidnapped by a masked bandit, but manages to escape, and ends up helping the police in the capture of the whole gang, getting a lot of money as reward.