The murder of her father sends a teenage tomboy, Mattie Ross (Kim Darby), to a mission of"justice",, involving avenging her father's death. She's a challenging old marshal,"Rooster" Cogburn (John Wayne), because he's got"grit", and a reputation to finding the job done. The 2 are connected with a Texas Ranger, La Boeuf (Glen Campbell), who's looking for exactly the identical man (Jeff Corey) for another murder at Texas. Their odyssey takes them out of Fort Smith, Arkansas, deep in to the Indian Territory (present day Oklahoma) to discover their man.