Miners have made a gold strike in western Montana, but the only men getting rich are the outlaws stealing it off Wells Fargo stagecoaches and freight wagons. Hardie goes undercover to the town of Aider Gulch to try to infiltrate the outlaw gang operating in the area and find out who is providing them inside information concerning gold shipments.
A man claims to have killed an outlaw who was wanted dead or alive. When he demands the reward Wells Fargo offered, Jim Hardie was ordered to Canada to identify the body since he was the only man alive who knew what he looked like. Hardie becomes suspicious when he learns the corpses face had been blown off by a shotgun blast. While he tries to learn more, the real criminal plots to kill the only man who can identify him.
The son of a dead man accused of robbing a Wells Fargo stage discovers an empty strong box in the attic of his farmhouse. The boy is still convinced that his father has been falsely accused and asks Jim Hardie to help find the real culprits.
A rich gold strike in Pleasant Valley has the Wells Fargo company scrambling to set up a new stagecoach run linking the boomtown with San Francisco. Hardie is detailed to find a trustworthy shotgun guard for the run and, of the objections of the branch manager, selects the son of a disgraced Wells Fargo employee to protect the gold dust and bullion being shipped.
Hardie picks up a valuable shipment in Matamoras, Mexico and isn't pleased when a dude and beautiful woman insist on becoming passengers on the stagecoach he will use to deliver the gold to a remote Texas town fighting Mexican bandits all the way.
Sam Bass and his gang have a hideout so secluded that no lawman has ever located it. From this stronghold they strike repeatedly, paying special attention to Wells Fargo shipments. Jim Hardie is ordered to infiltrate the gang so that he can learn where Bass's gang holes up between raids.
While transporting a prisoner, Dan Lingle, to stand trial for robbery and murder, Hardie's stagecoach is attacked by the outlaw's old gang. Among the passengers on the embattled coach are the Lingle's estranged wife and son and the outlaw determines to stand with them rather than to return to a life of crime.
When a Wells Fargo agent dies and fifteen thousand dollars is discovered missing from his office, the company orders and investigation. Jim Hardie isn't convinced the man died of natural causes and believes the money was stolen by whoever was responsible for his death. He gets a job in the local gambling hall to learn more about the man or men who could have been responsible for the crimes.