Ridin' the Lone Trail

Bob McArthur arrives in a small town to help Sheriff Carson capture a band of mysterious road agents. Bob works undercover as a ne'er-do-well cowpoke and, as his first assignment, helps to guard mine owner Furman's latest gold shipment. Despite Furman's attempt to hide the gold by sending two stagecoaches, Bob's protection is not enough and the coach with the gold is ambushed. Just before dying, the coach's driver tells Bob that the "white horse" was present at the robbery. Carson explains to Bob that the horse, named "White Peril," belongs to Joan, daughter of ranch owner Randall, and is always spotted at the scene of the crime. His trail invariably is lost, however, and Joan's assertion that no one but she can ride him has led to a dead end. Randall, who is also half-owner of Furman's mine, hires Bob to investigate. Bob is immediately taken with Joan, but runs afoul of her would-be suitor, Dusty Williams, who attempts to shoot White Peril when the horse reacts negatively to him. Bob trounces Dusty in a fistfight, after which Randall's foreman Peters voices his opinion that White Peril is indeed a killer. Things calm down and Bob and Joan have a pleasant time at a dance that night. The next day, Bob takes White Peril to the basin from which he mysteriously disappears after each robbery and attempts to follow him through the secret pathway. He is captured by Dusty and his companions, Pedro and Sparks, and the desperados plan to present him to their boss. While the boss, who wears a mask, confers with Dusty, Bob makes his escape and becomes suspicious when Joan apppears at the hideout. Bob believes Joan's plea that she merely followed White Peril and is innocent of any knowledge of the gang. Carson alerts Bob that there will be another shipment soon, and warns him that tension is high, for Randall and Furman suspect each other of masterminding the robberies. Bob returns to the ranch, where Joan has filled Peters in on the latest events. Peters then returns from the barn, claiming he was shot by the masked chief, while the gang ties up Joan. Bob watches from a distance as the gang leaves to get the gold shipment, and then captures Pedro, who was left behind to find him. After putting on Pedro's clothes, Bob frees Joan and chases after the gang. The chief, Dusty and Sparks succeed in getting the gold from the mine office and are about to make their escape when Bob finds them. The chief attempts to flee on a railroad handcart after Bob shoots Dusty and Sparks, but Bob catches him. Carson and his posse discover that the gang's tipoff man was Furman's worker Irving, and Bob unmasks the chief and reveals Peters, who only pretended that he was shot. Peters confesses that he trained White Peril to help with the robberies, and Bob and Joan happily close the case with a kiss.