Daughter of Don Q (1946) is a 12 chapter Republic movie serial. It combines elements of the B-Western genre with contemporary crime films, especially the popular "land grab" plot in which the villain attempts to steal apparently worthless land from the heroine (in this case) because he secretly knows it is worth a fortune. In this case, Dolores Quantero, is the rightful heir to extremely valuable metropolitan land which another familt member, Carlos Manning, wants for himself.

Delores Quantero, played by Lorna Gray, is the descendant of Zorro-style hero, Don Quantero, who was granted land by the Spanish crown. This grant, which is still legally valid, now covers the business district of the city. Another descendant, Carlos Manning, played by LeRoy Mason, has discovered the existence of this document and plots to inherit the fortune by murdering his relatives. Delores teams up with Cliff Roberts, played by Kirk Alyn.

This is one of the few (possibly only) serial where there is not only a female lead, but she fights and wins (okay she also gets tied up by the bad guys quite a bit, but she across 12 chapters she knocks out a quite a few villans.)

text from wikipedia