Thundering Caravans

U.S. Marshal Allan "Rocky" Lane is assigned to stop a gang of outlaws who are robbing ore shipments from the gold mining town of Edgewater. After reporting to Nugget Clark, the sheriff, and his deputy, Dan Reed, Rocky meets other Edgewater citizens: Henry Scott, the owner of a mine, who is angry about the robberies; Henry's daughter Alice, who is sweet on Dan against her father's wishes; and Deborah Cranston, the newspaper editor, who is backing her brother Bert for sheriff in the next day's election. After badgering Nugget, Deborah meets with Bert, who is in cahoots with the outlaws who shot the driver. She orders that the stolen ore be moved from their cave hideout while people are voting in town, and later tells Bert they will be able to make more money when he is sheriff. Deborah then gets a surprise visit from a recently escaped convict, Ed Brill, who tells her that Dan was his cellmate in prison. After Ed announces he is blackmailing Dan, she maliciously writes her next day's news story about the deputy. That evening, Dan, who has reformed after serving his time, tries to arrest Brill during his blackmail attempt, but Brill escapes just as Rocky and Nugget arrive. Rocky chases him to a nearby ghost town called Midas, but loses him when Brill enters the old hotel, which has a secret doorway that leads to the gang's hideout. Later, Dan tells Rocky about the blackmailing, and how he got caught up with outlaws when he was young. Nugget, who is the only person in town who knows Dan's history besides Alice, expresses confidence in him. The next morning Rocky and Nugget form a posse of trusted miners to search Midas when necessary. Meanwhile, Deborah plans a way to frame Dan for a payroll robbery. As is their practice, Bert gives Dan the bag containing the miners' payroll, which he is to deliver to the mine. After Deborah learns that Rocky has decided to accompany him on the trip, she sends a man to shoot Rocky and leave Dan unharmed. When the man ambushes them, Rocky sends Dan ahead to deliver the money, while he pursues the outlaw, and eventually kills him in a gunfight. Returning from the mine, Dan sees the outlaws carting the ore out, and is captured and taken to their hideout. Meanwhile, Henry finds only rocks in the payroll bag. Having read the damaging article about Dan in that day's paper, Henry, who is on his way to report the missing money, warns Nugget that his men will shoot Dan on sight. After he leaves, Nugget and Rocky discuss the situation, noting that if Dan had planned to rob the payroll, he would not have delivered the bag. They also consider that Bert had the bag first, and that Deborah must have learned about Dan's background from Brill. Connecting the robberies to the Cranston family, Rocky devises a plan. Nugget tells Deborah that the outlaw Rocky shot is confessing and that he will soon have a scoop for her. Rocky trails Deborah and watches as she whispers a message to Bert, who rides off. Rocky chases Bert toward Midas, but eventually slips ahead of him so that he arrives at the ghost town first. Through a crack in the wall, Rocky watches as Bert enters a trapdoor in the floor of the building, and then quietly follows him into the cave. He finds Dan there alone, as Bert and his henchman are loading the last of the wagons. When the outlaws return, a fight erupts, which Brill soon joins. Dan and Rocky subdue all but Bert, who escapes to a wagon. Before chasing him, Rocky tells Dan to round up the posse and stop the wagons that left earlier. Rocky catches up with Bert, and after a struggle, arrests him. Later Nugget, who won the election in a landslide victory, gleefully puts Deborah and Bert behind bars. Dan, a hero for leading the posse that retrieved the stolen ore, has Henry's blessing to marry Alice. With everything in order, Rocky rides back to headquarters.