Set in mission-era California, the story follows a mysterious, daring rider who challenges corrupt soldiers and officials while aiding oppressed villagers. Episodes alternate between tense skirmishes, clandestine tunnels and disguises, and quieter scenes of life around the presidio and mission, including the abuse of a neophyte by a brutal sergeant. Romantic complications with a young woman intertwine with revelations, betrayals, an unmasking, and fatal violence, as secrets buried in the presidio and on the highway come to light. The narrative blends action, intrigue, and romance to examine loyalty, honor, and resistance within a decaying colonial society.