In Self Defense.

The recently orphaned Enriqueta has to work to earn a living; She finds a job with the widower Julio Mancera, for whom she works as governess for her little daughter. After a while, the two fall in love and get married. But then, Julio's cousin Eva returns from Europe and tries to separate the couple. She is almost successful, but her plans are thwarted at a party she throws for Julio and his friends, where she is surprised by Julio, Enriqueta, and the other guests in a compromising situation with Julio's best friend, Mauricio.