During the period of New Spain, the dictatorial Juan Mendoza, overseer of the San Fernando Valley seals the area off and forbids anyone to enter or leave. When he seeks to marry Maria Garcia, daughter of the blacksmith, her Irish boyfriend Michael O'Brien challenges Mendoza.
At the same time a small vein of gold in the area is discovered with the gold concealed inside a church bell.
Michael and Maria seek to escape to Monterey to seek the help of the Governor of Alta California.