Reese, Chad and Joe chase Durkee, a wanted man, into Captain Parmalee's office only to find out he is seeking amnesty in return for information about the Jamison Gang. The three of them are assigned to work with him and sent to Arillo. Meanwhile, Sam Burns is trying to force Annamay, a widow with two children, off her ranch so he and Jamison can get the silver bars the Gang buried in her barn's floor. The Rangers help Annamay and the children repair her wagon wheel and she takes a liking to Reese, who the children are soon calling ""Uncle Reese"". Annamay learns of the silver and switches it to a new hiding place. Jamison and Gang threaten Annamay and the children as the Rangers hurry to rescue them and recover the silver.

Jake Murdock wants revenge on Parmalee for sending him to prison. His plot involves Dr. Duvain who has a mind-controlling drug that can make a man kill his best friend. To remove suspicion they plan to have a ranger kill the captain. Reese is picked and undergoes a series of injections to prepare him for the murder. A $5 gold piece is the key to controlling Reese, whenever he sees one he is to obey the next verbal command which results in Reese allowing an outlaw to escape, immersing himself in a horse trough (Go soak your head) and busting up the saloon. Chad investigates the doctor's background and reads books about chemistry and the brain. He figures out what is causing Reese's strange behavior and convinces Parmalee of it who then devises a way for the plan to backfire on Murdock and the doctor.

Grover's Bend storekeeper Mr. Tinker telegraphs Parmalee that cattleman Ed Garmes is bullying a sheep raising religious group called the Peaceables, who refuse to defend themselves because of their beliefs. Chad, Joe and Reese are sent to protect them. Reese hurt his back in Laredo and is in need of bed rest by the time they reach Ernest Snilly's sheep ranch. Chad and Joe head into Grover's Bend while Reese is cared for by Snilly's daughter Delia who does her best to convert Reese to their non-violent ways. A pacified Reese is roughed up by Ace Brady and the other toughs Garmes has hired while Chad and Joe set to jailing half the gang, arresting one or two at a time. Ace and the gang ambush Chad and Joe who take refuge in the jail. Chad tries to snap Reese out of his new beliefs by convincing Garmes that Delia loves him but wants him to be more forceful. He attempts this at the Snilly house where Delia cracks him on the head with a frying pan when he touches her. Reese comes to