The High Chaparral - Season 3 Episode 21
The Reluctant Deputy

Blue is the victim of a practical joke that finds him enlisted as a temporary lawman Tricked into being sworn in as a deputy marshal by Manolito and his Uncle Buck, Blue is forced to take the job seriously when the towns regular lawman departs leaving him in charge of the entire town. Blues new authority enables him to exact a sweet revenge on Manolito and Buck.