Arizona Whirlwind

While riding the trail with his young friend Donny Davis one day, United States Marshal Bob Steele witnesses a band of Indians attack a stagecoach. After the driver is shot, Bob sends Donny to the stagecoach relay station to summon his fellow lawmen and saddle pals, Hoot Gibson and Ken Maynard, while he rides after the runaway coach. When the coach loses a wheel, Bob guides the crippled vehicle into the rocks for cover. Soon after, Hoot and Ken arrive and Hoot tricks the Indians by playing reveille on Donny's bugle, leading them to believe that the calvary is coming. After the Indians flee, Bob and the boys accept the gratitude of passengers Ruth Hampton, who is traveling to Sonora to work at her mother's restaurant, and Jim Lockwood, who has come to build a telegraph line. When Donny reports that he saw a man watching the Indian attack, Bob begins to suspect that their assailants were renegades disguised as Indians. As Bob and the others accompany the coach to the relay station for repairs, Ace, the man whom Donny saw, rides into town to inform his boss, banker Steve Lynch, about the failure of the attack and the appearance of the three strangers. Lynch then instructs his henchman, Duke Rollins, to recover the valuable cargo that the stage is carrying. After the wheel is repaired, Bob offers to drive the stage to town while Hoot and Ken ride ahead as scouts. When Hoot and Ken come upon a pile of logs blocking the road, they glance into the hills and see Duke and his gang waiting in ambush. The two gallop back to the stage to warn Bob, who then hides the stage behind some rocks, thus foiling the attack. After safely delivering the stage to town, Bob, realizing that it must be carrying something of value, conceals it in a stable where he, Ken and Hoot begin a thorough search. Having tracked the stage to the stable, Duke summons Lynch there. Lynch informs Bob that he owns an interest in the stable, and orders him to remove the stage. After returning the coach to the relay agent, Bob, Hoot and Ken agree to help Lockwood string the telegraph lines, hoping that the job will conceal their true occupation as U.S. Marshals. At the bank, meanwhile, Lynch informs his men that he suspects Bob and his friends are lawmen and orders their demise. When Warren, a crooked jeweler, arrives, Lynch produces a keg of axle grease that he has removed from the stage. Hidden inside the grease are stolen diamonds which Warren has been hired to cut. Bob, in town to visit Ruth, sees Duke and his thugs ride out and telegraphs Hoot and Lockwood that trouble is headed in their direction. Duke spies Ken stringing telegraph wire, Duke accuses him of trespassing and orders him to leave. Witnessing the confrontation, Hoot electrifies the wire, shocking Duke and his thugs and allowing Ken time to pull his gun and escape. In town, meanwhile, Polini, the mastermind behind the jewel theft, arrives, impatient for the cut stones. To pass the time, Lynch accompanies Polini to Ruth's restaurant, and there Bob overhears them discussing the theft of the diamonds. When Donny enters the diner and loudly greets Bob as a U.S. Marshal, a fight ensues between the lawmen and the thieves. After instructing Donny and Ruth to watch Polini and Lynch, Bob flees to join his friends at an abandoned mine that they have established as a telegraph sub station. Finally certain that the three strangers are lawmen, Lynch sends Duke and the gang after them. Tracking Bob to the mine, the outlaws block the entrance, trapping the marshals inside. In town, meanwhile, Donny and Ruth eavesdrop as Polini orders Lynch to lock the diamonds in his safe. After Donny climbs in through a window and sneaks into the safe, Lynch slams the door, locking him inside. When Ruth telegraphs the lawmen about Donny's peril, Bob decoys the outlaws, thus allowing Ken and Hoot to escape. The trio then gallop into town and Ken sneaks into the bank while Bob and Hoot hold off the outlaws. When Lynch, terrified, declares that he is planning to surrender, Polini shoots him. Just then, Ken reaches the safe, and as Polini takes aim at him, Hoot bursts into the room and shoots the thief. After Ken opens the safe and frees Donny, the marshals retrieve the stolen diamonds. Their job done, the trio bid farewell to Donny, Ruth and Lockwood and ride off into the sunset.