[1] Mario De Santis, an enterprising trade representative who sells toothpastes, regularly married to Valeria, sees his life upset by the accusation of being bigamous.

Accompanied to the police station, he is confronted with a certain Isolina Fornaciari, whom he would have married in Forlimpopoli a few years earlier.

Mario, furious at the accusation, goes into de facto ways with Isolina's father, with whom he has a fight so much that he is put under arrest.

A friend of Mario's, met in prison, realizes that it could be a case of the same name and sets out to travel all over Rome in search of Isolina's real husband.

Having served the small sentence inflicted on him, Mario can finally return to the arms of his family, who are waiting for him at the exit of the prison.