Calhoun outbids his old nemesis Sam McGinty in an auction for a new boiler which both men need. But shortly afterward, the boiler is stolen at gunpoint and taken, along with Dave, to an impoverished town which needs the boiler to revive its only source of income. Dave soon finds himself in a predicament as he comes to sympathize with the townspeople.
Barnabas identifies his coworker and friend Billy Pardew as the killer of a store clerk, though only on the basis of his boots. The obviously biased judge, a man known to be too quick to hang defendants, asks Calhoun to act as Billy's defense when no attorney agrees to take the case. And Billy's uncles are determined to stop his being hanged any way they can.
Calhoun's acquisition of a right-of-way for the railroad is threatened when he takes the side of allowing a band of Indians---mostly old people, women, and children---to go through it on their way back from the reservation to their ancestral home. The townsmen who agreed to the right-of-way do not want them to cross it, and insist that Calhoun keep them only on the narrow strip he owns or forfeit it, and hence lose the railroad.
Ben puts himself in the center of a conflict when he decides to help French monks establish a vineyard. But trapper Ike Bridger and his friends see it as prime beaver habitat and are unwilling to give it up without a fight.
Calhoun realizes that four members of an outlaw gang have surreptitiously boarded the train. But he decides to not let them know he is on to them until he knows their plan, and can devise one of his own to stop them.
Young Frank Wyatt is accidentally shot in a fight with Barnabas, who thought he was behaving improperly with a young woman. Calhoun tries to take Frank to the nearest doctor by using the train, but Frank's powerful father forces both Frank and Barnabas off and takes them to his ranch. Though this action aggravates his son's wound, the elder Wyatt plans to kill Barnabas if Frank dies, even over Frank's objection.
Although Calhoun discovers that the man who saved Julie and Barnabas from ambush is a former railroad engineer branded as a traitor during the Civil War, he still decides to hire him, despite Dave's objection and his own suspicions. Unfortunately, the man still has his old associates riding with him and they are all planning to steal the gold that the train is carrying.
The ownership of a luxurious railway car is disputed so Ben takes possession of it even though it contains passengers. He ruins the plans of an outlaw gang that had plans to hold everyone and the car for ransom.
A dying marshal deputizes Dave (who in turn also deputizes Calhoun) to transport his prisoner to Doan's Junction to be tried for murder. But other members of the killer's gang have boarded the train and are planning to break him free. The prisoner also sees an opportunity for escape in a young woman who is being forced into marrying a wealthy man and clearly doesn't want to.