In 1840, American soldier of fortune Phillip Kent is hired by the Mexican government to take a shipment of rifles from Mexico City to California. Upon his caravan's arrival on the outskirts of Los Angeles, Phillip and Pio, his Mexican associate, rescue aristocrat Marguerita Novarro and Filomena, her maid, from a runaway carriage. Later that night, Phillip orders the caravan to leave immediately for the north after their camp is infiltrated by two Spanish royalists. He is unaware, however, that Marguerita and Filomena have stowed away among their cargo, having missed the northbound stagecoach to Santa Barbara. The caravan arrives in Santa Barbara with its extra cargo during the Fiesta of the Harvest, but rather than accepting payment for safely transporting the wealthy Marguerita, Phillip merely asks for the honor of the first dance with her during the festival. The two quickly fall in love, but when Phillip goes to call upon Marguerita the next morning, he discovers that she has already left town. The caravan then resumes its trek northward, but is ambushed along the way by Spanish royalists. They escape the trap, however, and arrive safely at the Mexican army post in Monterey, where Phillip is delighted to be reunited with his best friend, Lt. Carlos Ortega. Later, Phillip's delight turns to shock, as he learns that Carlos is engaged to Marguerita. In order to protect his friend, Phillip pretends not to know Marguerita, and she agrees to go along with his ruse. That night, Carlos is attacked and wounded by royalists attempting to steal the new rifles. Manuel De Roja, one of the royalists, is captured by Phillip, who then turns the prisoner over to Major De Roja, the post's commandant. Unknown to Phillip and the others, however, is the fact that De Roja is Manuel's brother and a royalist. De Roja later arranges for his brother to be killed while trying to escape in order to protect his true allegiance. With the injured Carlos confined to bed, Phillip is asked to act as Marguerita's escort at numerous engagement parties. Marguerita soon confesses her love to Phillip, so he attempts to leave Monterey, only to be followed by Marguerita. She convinces him to return to Monterey and tell Carlos all, but the two are instead captured and taken to De Roja's royalist hideout. There, De Roja tells Phillip that he plans to take over the army post with the help of royalists pirates, led by Captain Cordova. Pio, having discovered his friend missing, returns to the army post and uncovers the royalist plot by torturing De Roja's associate, Sergeant Gomora. Meanwhile, a jealous Carlos goes in search of Phillip and Marguerita, and he too is captured by the royalists. Phillip and Carlos escape, however, and Phillip kills De Roja in a sword fight. At the same time, the pirates, without the element of surprise, are routed by the Mexican soldiers as they attempt to land at the beach front. Phillip and Marguerita are later married, with Carlos' full blessings.