Koko the Horse

Postal inspector Rex Allen (Rex Allen) is sent to California to speed up mail delivery and plans a contest to determine if the stagecoach line run by John Brockway (George Lloyd) or Roger McCall's (Grant Withers) clippers can deliver faster, but duplicity undermines the competition. McCall, who has been stealing money from the mail, arranges for explosions, arson and murder to slow his competitor, but hard-ridin' Rex may outwit the saboteur.

When railroad contractor John Anchor (Roy Barcroft) tries to exploit Apache chief Black Hawk (Leonard Nimoy) and his tribe, Bureau of Indian Affairs official Rex Allen arrives on the scene to prevent the conflict from escalating into a war. But things get complicated for Rex, especially since his black sheep brother Jim (Gil Herman) works with Anchor. Slim Pickens and the Republic Rhythm Riders co-star in this musical Western.

In 1926, former Cavalryman Rex Allen (Rex Allen) is pressed back into service when the Cavalry needs land in order to test the efficiency of horses compared to new, mechanized tanks. But ranchers worried about losing their grazing areas cause problems. Along with his pal Slim (Slim Pickens), Rex investigates the sabotage that killed a soldier and obtains justice for his girlfriend, Terry (Elaine Edwards), who's being targeted by the saboteurs.