Rancher Rex Allen captures a bandit, Delgado, a henchman for crooked Sheriff Webb and saloon owner Mike, who run the town to suit themselves, but Rex forces the sheriff to jail Delgado. When Marge, who runs the town newspaper tells Rex she is afraid to attack the sheriff in print, Rex decides to run for sheriff. Webb and Mike frame Rex and his partner Slim on a murder charge and they are jailed. The sheriff arranges for them to escape but not before he has posted three gunmen outside the jail to kill Rex and Slim as they escape. For animal fans or those who prefer to know the actual credits shown on a film, “Koko, the Miracle Horse” is billed above the title with Rex Allen, and is also billed 9th (following Julian Rivero) in the cast credits.