Hickok has a fight with Teaspoon and agrees to go to work in a brothel where the madam, Grace Rollins, has taken a fancy to Jimmy. But deceptions abound: Grace has her eye on a secret Army cache of weapons she plans to sell on the black market, and Jimmy has his eye on her illegal schemes.
Cody and The Kid, on special assignment, stop for refreshments in a little town called Prosperity. When The Kid tries to defend a woman and gets into trouble with local lawmen, Cody suspects that not all is right with the strange town. He seeks the Riders' aid to help rescue The Kid from terrible punishment.
While away from Sweetwater on a run, Lou impulsively buys a dress and tours a new town as the young woman she is. An insurance salesman, Tyler Dewitt, takes Lou out to dinner, and she becomes enamored of him. But is the polite salesman all he appears? And what will The Kid think?
Evan, Emma's estranged husband, returns, reminding Emma of her difficult past and driving a wedge between her and Sam. But despite any reluctant loyalty she feels for him, even Emma must admit that Evan's behavior is suspicious. Just what is his link to a terrible stagecoach massacre?
The Army requests a rider to deliver a special dispatch, and Cody volunteers for the job. Along the way, he encounters brigands, a bear, and a desolate widow, but he remains committed to his task. Meanwhile, the Riders tend to an abandoned baby.
At a town celebration, Buck falls for the daughter of an ambitious banker, but her motives in the relationship are questionable. Meanwhile, the Riders help a desperate woman whose husband was killed by the banker's henchmen, and they investigate accusations of illegal claim jumping.
When the Pony Express ownership wants to move the mail route north through Sioux burial lands, they send a college boy - Ambrose - to secure the arrangement. Ambrose has a serious case of hero worship for Hickok and, despite his naiveté, he refuses to be a pawn to anyone's manipulative plans.
Jimmy reunites with a friend and rival from his youth, Brad, both of whom trained under a Machiavellian mentor named Enright. When Enright's daughter goes missing, Jimmy helps Brad try to find her. But why did Clara really run away, and what does Enright have to do with corrupt land prospecting?
A corrupt businessman from Sam's violent past, Van Dorn, arrives in Sweetwater as the saloon's new owner. Van Dorn's henchmen are appointed as the town's new racketeering law enforcers, ousting Sam Cain as marshal. When Sam is accused of murder, Teaspoon, the Riders, a reluctant witness, and an alcoholic lawyer come to his aid.
When aging survivors of the Alamo are found murdered, one by one, Teaspoon and his old friend travel to Texas to get to the bottom of the killings. Jimmy and Buck follow in search of the truth and to lend a hand, and they learn that there is more to their mentor's past than they realized.
The Kid plays on his Virginia roots in order to infiltrate a gang of renegades led by an anti-government rebel named The Hawk. Meanwhile, an ambitious and head-strong Army captain begins to crack down on dissent in Sweetwater in his own bid to reveal and capture The Hawk and his men.
In part two, Jimmy joins The Kid as infiltrators into The Hawk's gang, and Ike befriends an abandoned mail-order bride named Annie. When Captain Lewis will not listen to the Riders with regard to The Hawk's plans, the citizens of Sweetwater must take up arms to defend their town against the renegade onslaught.
The Buzzard, a creepy man from Teaspoon's past, shows up with his evil looking dog and creates misery for those who cross him. The young riders aid Rachel by taking on the Browning clan, one who she's accused of killing.
When Thompkins' wife and daughter who were taken by Indians years ago are found, they return to him. But also with give is a boy whom his wife says was fathered by the Indian who took them. Upon learning this, he pushes them away. His daughter wants to go back cause she is betrothed to a member of the tribe. And if she doesn't go back he will come after her.
Ike is beaten by some ruffins because of his deafness and becomes bitter about life. He meets a young Arthur, who is terminally ill but remains excited about everything and is thrilled to meet his heroes, the riders.
The Kid brings in suspected horse thief Dyson to Sheriff Lambert but the prisoner dies in custody. Lambert, who's extorting the town's citizens, finds himself up against the dead man's family and the other riders when the truth comes out.