Ken Maynard's exceptionally intelligent horse, Tarzan the Wonder Horse, is the star of this western about evil cowboy Steve Frazer (Welch) who gathers horses for slaughter, whose meat is sold to pet food manufacturers. The wild horse Tarzan frees the doomed horses from their corrals, and Frazer convinces the Sheriff that Tarzan is a threat and can be shot on sight. Local cowboy Ken Benson (Maynard) and rancher Pat Riley (Kennedy) work together to clear Tarzan's good name and put Frazier behind bars for his evil deeds.

When a band of American Indians breaks a treaty with the federal government, U.S. Marshals Ken Maynard and Hoot Gibson hit the trail with captured outlaw Duke Dillon (Jack La Rue) to find out what sparked the uprising. They discover clues that point to corrupt Indian agent John Hampton (Kenneth Harlan), but meanwhile, the bandit Dillon pulls a fast one on the marshals, and soon everybody's getting ready for a showdown.

Two cowboys try to protect railroad workers from rampaging Indians.

An internationally-notorious criminal scientist returns to the US to sell his latest invention, a disintegrating gas, to a foreign power. When he arrives, however, he is spotted by a young Coast Guard man, whom he kills - and thus earns the enmity of the entire US Coast Guard, but especially the murdered Guardsman's older brother who, together with his reporter-girlfriend and her comical photographer, vigorously sets to tracking him down and interfering with his plans to develop the city-melting gas in quantity. A Republic Serial in 12 Chapters.

An eclectic group of people are stalked by a masked killer in an old mansion.