Koko

Anchor is building a railroad and to get cheap labor he gets Black Hawk's Indians to attack and burn the incoming wagon train. This forces the settlers to work for Anchor and he pays them in devalued scrip. When Rex figures out Anchor's swindle, Anchor gets Black Hawk to capture him. When Anchor turns on Black Hawk and shoots him, Black Hawk gets a chance to repay a debt to Rex.

Rex Allen and Slim Pickens are sent from Washington, D.C. to California in 1850 to speed up deliveries of mail to the goldfields, and find a destructive feud raging between two stage-line owners, Sam Sawyer and John Brockway. In their attempts to have their stages and drivers first on the dock to get the mail brought East by ship, the two have damaged each other's equipment and schedules to the point that no consignment of mail reaches the goldfields intact or on time.

Rex Allen ('Rex Allen'), a U. S. government veterinarian, rides into the picturesque town of Pine Rock, near the Canadian border, to take the place of the regular vet who is on vacation. Used to doctoring animals in Texas, Allen finds out that herein the heart of the fox-farming industry, he is to doctor the most finicky and high-priced of fur on four feet. On the farm of Mel Richards (Tom London), Allen learns the habits of the valuable creatures from Richard's niece, Jane (Mary Ellen Kay, and her ten-year-old brother Danny (Jimmy Moss'), and on his own learns that the trusted owner of the trading post, Steve Baxter (Roy Barcroft) heads a gang that is smuggling counterfeit money across the American/Canadian border in the fox cages.

One-time cavalry officer Rex Allen, between jobs as a star rodeo rider, is asked by his former commanding officer, Colonel Bigelow, to help settle a dispute between the army and local ranchers. The cavalry has commandeered a large parcel of land needed to test their newly-designed tank and prominent rancher Jenson has encited the locals to rebel at this intrusion. It is up to Rex and his sidekick, Slim, to thwart Jenson and convince the residents that these army tests are essential.

A greedy rancher is charging excessive prices for access to the area's only water supply, extorting the smaller ranchers in the area. A water diviner teams up with a cattle buyer to force the villain to share the water with his neighbors.

When an oil discovery is reported at Paxton, Oklahoma, Marshal Rex Allen immediately suspects that where there is oil, there is trouble. Rex arrives just as a band of desperadoes stage a bank hold-up and escape with $25,000 which ranchers have invested in prospective oil drillings.

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.

Rex Allen against diamond smugglers down Laredo way