Diego de la Vega, an eighteen-year-old Spanish nobleman, returns to his California homeland after studies in Spain. He discovers the region oppressed by Commander Raymond and Lieutenant Gabriel. Witnessing injustice, he becomes Zorro, a masked vigilante defending the weak. Operating primarily at night, he uses exceptional swordsmanship to thwart authorities, leaving his distinctive "Z" mark as a symbol.

In civilian life, Diego deliberately portrays himself as clumsy, cowardly, and disinterested in confrontation to avoid suspicion. This facade strains his relationship with his childhood friend and sweetheart, Lolita Prideaux, who scolds him for his perceived weakness. Unaware of his secret, Lolita develops romantic feelings for Zorro, forcing Diego to navigate her admiration for his alter ego.

Diego is aided by Bernard, a nine-year-old orphan adopted by the de la Vega family. Discovering Diego's secret early, Bernard becomes his trusted aide "Little Zorro," gathering intelligence, creating diversions, and assisting missions. Bernard's youthful energy and loyalty prove integral. Diego's animal companions include his horse, Viento, used for swift travel and escapes, and his lazy hunting dog, Tackle.

Throughout his crusade, Diego maintains a calm, strategic demeanor, contrasting with impulsive allies. He balances his reluctant nobleman persona by day with his decisive hero role by night, leveraging intellect and physical prowess to protect vulnerable communities, expose corruption, and ensure safe passage for those fleeing oppression.