Mistress in title of Jenaro Martusano and eager to be married by him, Filomena is nevertheless convinced that her lover is cheating on her. So she uses the services of Remigio, a detective with methods that are ambiguous to say the least. In fact, Jenaro has an affair with Carmela, a young nurse with whom he indulges in shameless sexual games. But, when Jenaro returns home, he finds a dying Filomena who extracts from him the promise to marry her in just marriage. Troubled, he accepts. Filomena therefore becomes “Madame Martusano” and…immediately recovers her health. Furious at having been fooled, Jenaro threatens to divorce her. But, the beauty has more than one trick up her sleeve...