The Young Land: American gunslinger (Dennis Hopper) kills a Mexican man in California immediately after the Mexican-American war. The killer is arrested and put on trial for murder with the Hispanic population waiting to learn of American justice.
In 1848, after the end of the Mexican–American War and with the advent of California statehood, an American gunslinger named Hatfield Carnes (Dennis Hopper) kills a Mexican man in California. He is arrested for the murder by Jim Ellison (Patrick Wayne), a former United States marine and now sheriff with neither a gun nor a badge.
Appointed by prominent local businessman and politico Don Roberto de la Madrid (Roberto De La Madrid), Ellison has designs on de la Madrid’s spoiled daughter, Elena (Yvonne Craig). By the book Judge Millard Isham (Dan O’Herlihy) arrives in town with Deputy Marshal Ben Stroud (Cliff Ketchum) to conduct the trial.
Wanted tough guy Lee Hearn (Ken Curtis) has problems of his own with the law, but is willing to help Ellison as a deputy. Carnes is then placed on trial in the new Mexican Cession territory with the Hispanic populace waiting to learn if American justice will convict Carnes.