In the sleepy, out-of-the-way Spanish colonial hamlet of Los Angeles, young Diego de la Vega is determined to discover the cause of an outbreak of cattle rustling and the accompanying disappearances of some of the pueblos craftsmen. Eventually, he and his best friend, Bernardo, find that an evil aristocrat, don Moncada, is responsible for the kidnappings and is planning to set up his own kingdom. Diego's fearless, upright father leads a small army...