A bandit who robs both Americans and Mexicans is causing each side of the border to blame the other. Hoppy has to settle matters.

Two deputies go undercover to save a scientist from his evil kidnappers.

Boston pharmacist Tom Craig comes to Sacramento, where he runs afoul of local political boss Britt Dawson, who exacts protection payment from the citizenry. Dawson frames Craig with poisoned medicine, but Craig redeems himself during a Gold Rush epidemic.

Bullfighter Juan Gallardo falls for socialite Dona Sol, turning from the faithful Carmen who nevertheless stands by her man as he continues to face real danger in the bullring.

It is 1853 and settlers are pouring into California which means trouble for the old Spanish landowners. The El Dorado Mine Co. wants the land of Don Ortega for the minerals and is using the settlers and his friend Don Carlos to take the land over. But Tucson is on the side of Roberto and see's that something is not right with all the trouble they have been having. But the situation turns ugly for Don Ortega when Roberto is set up for a murder he did not commit.

Hoppy and new sidekick California Carlson head to California to help out Lucky Jenkins.

Easterner Madeline Hammond buys a ranch not knowing Hayworth is using it to smuggle ammunition across the border. When trouble starts, she brings back Gene Stewart ex-foreman who left the country after fighting with the Sheriff.