 The cattle herds of some Arizona ranchers are being stampeded and stolen, so the Arizona Stockmen s Syndicate sends ace investigator Steve Reynolds (Charles Starrett) in to find out who is responsible. Steve poses as a vicious gunslinger named Buck McCloud to work his way into the gang, and then becomes the Durango Kid to disrupt the activities he learns about. Adelle Roberts (as she was always billed at Columbia) is the loyal fiancee of town banker Grat Hanlon (Richard Bailey) who turns out to be the brain-trust behind the gang.