Francesco Salmarani, a well-known doctor from Treviso, suddenly finds himself with an overdraft bank account as his wife's father has come from America demanding the purchase of a large Palladian villa. Tired of his wife, Francesco consoles himself with Paola and then lets himself be ensnared by the very young and beautiful Mary, who has come as housekeeper and father-in-law's lover. The need to fill the administrative gaps and the dream of running away with Mary lead the doctor to organize a coup against his father-in-law who, linked to the mafia, managed to transfer a large dollar patrimony, stolen from the gang, to the villa. The presence of the boy allows the commissioner to exonerate his son-in-law, Mary and Felegatti, of the death of the old mafioso. However, everyone will be left without the dreamed treasure which will fall to Mary and the son of the Salmarani who flee together.