Columbia general purpose actor Bob Allen was briefly transformed into a cowboy for the studio's "B" unit in the mid-1930s. Allen stars in Unknown Ranger as a ranch ranger on the trail of rustlers. The gang has rounded up a wild stallion, in order to lure a prize horse away from a wealthy rancher. Bob tames the stallion and bushwhacks the baddies. Bob Allen didn't catch on with the fans, principally because he seemed out of place in the Great Outdoors; Allen would fare better when he left movies for the Broadway stage.