El perro del hortelano is a film based on the theatrical play of the same name by Lope de Vega, one of the most prominent Spanish writers of the Golden Age together with Cervantes, Calderón de la Barca and Francisco de Quevedo, among others. This literary play is marked by the comical approach of its author, who deals with the emotional complications of class conflict with cynicism and humour.
Diana, Duchess of Belflor, is a smart and attractive young lady who is in love with his secretary Teodoro, but he is engaged to Marcela, a lady-in-waiting of the Duchess. Diana, driven by jealousy and envy, tries to separate the two lovers.