An experienced eastern constable comes to Texas to show the Texas Rangers how modern police techniques can be used to do their job better. He doesn't help his case by stating most Texas Rangers are dirty and untrustworthy.
Arailroad man and his beautiful daughter who are old friends of Chad arrive in Laredo to offer Chad a job and maybe a wife. Joe and Reese with some help from the Captain try to prevent Chad from leaving the rangers.
Billy Harker's girl friend Laurie leaves Chad undressed and afoot while he is on Billy's trail. Joe and Reese are sent after Chad but Laurie gets the best of them until Joe decides to let Laurie take them to Billy without her knowing.
As punishment for fighting the rangers are sent to escort a wagon of buffalo hides. They add some female company to the trip not realizing they are caring a load of rifles being illegally sold to the Comanches.
Captain Parmalee sends Reese to Red River to pick up a shipment from St. Louis. Reese says a little too much on his way out of town. With rumors of a gold shipment coming into Laredo, Reese is being stalked by criminals.
Laredo is visited by a state senator who is held up on the stage with Parmalee. The rangers try to make amends but digger a deeper hole with the senator ultimately taken hostage when the rangers try to fake his kidnapping and rescue.
The rangers capture the Slaughter gang and the money they stole. The gang breaks out of jail and the money is stolen while the rangers and others attend a show put on by a lady of culture who Reese helped sell tickets.
Cletus Grogan is convinced he's a jinx because disaster follows him everywhere. When Joe is captured by bank robbers, and his fellow Rangers appear to be in a crossfire, Reese pretends to allow Cletus to rescue him to break the curse.
The Army challenges the rangers to fight on July 4 but the Pryor gang stealing silver from a local mine is messing with their plans. The rangers scheme to get their man in the ring while the boss of the ring has a surprise for the rangers.
The Rangers are told to stay in Laredo but Chad and Joe scheme to go to San Gill not knowing Parmalee is there. Reese follows once he learns what they did but true to form all three get into trouble but manage to save Parmalee's life.
Chad and Joe routinely take advantage of Reese. When a payroll is stolen by a group lead by French officers, they con Reese into spying on the them. His actions put him in front of a firing squad for which the men tell him he won a medal.
Parmalee sends Chad and Joe to Guarded Wells to wipe out the Ramirez gang. Once the job is done, the people of the town provide free hospitality. Not wanting to leave it, they make up a story about the Calico Kid which goes out of control.
A innocent man is convicted of murder. A man is hired to find the real killer. He plots the escape of a second man who hopes will lead him to the guilty party. Reese, however, almost messes up his whole plan by nearly catching the escapee.
Two young stranded British actors are rescued from the law for being unable to pay their bills by Chad. When one decides to play the part of a minister as a con, he is forced to marry a couple putting them in a perilous situation.
New ranger Cotton Buckmeister is assigned to return documents to Uvalde County but included in the documents is one for his arrest for Breach of Promise. He was to marry the sister of the crooked Judge there.
While rounding up a gang of horse thieves, Joe stumbles across a young boy who is working for the outlaws. Joe and Chad take him under their wing and the boy proves his worth when a laid-off gang of gunslingers decides to take over Laredo.
Reese and Cotton rout a couple of gringos terrorizing a small Mexican village. One of the owlhoots threatens to return with a gang of gunfighters so Reese agrees to teach the villagers how to defend themselves.
Reese has a plan to use Joe as bait to catch Linda Little Tree but Parmalee doesn't want to try it. Being upset the Rangers ignore Parmalee's orders and botch his own plan for catching Linda Little Trees. Joe tracks them but is caught.
After Reese leaves two nuns near Massacre Mission, Joe and Chad must go there to remove the nuns. They find the threat from the Comanches to be non-existent but find outlaws are an issue plus they have to do manual labor for a change.
Reese and later Joe try to go undercover to catch bandits at a remote bar. However, Reese is recognized leading to his capture and later Joe's. A battle develops between two two women over one of the bandits giving the Rangers an opening.
Reese is ordered to find an English schoolmaster who was detained en route to Laredo. An ex-con who Reese arrested several years ago spots him and determines to settle the score with the Ranger and his British charge.
After the Morgan gang, the Rangers catch a wounded member and his teen daughter. In helping the wounded man, they come to worry about the girl as they await the rest of the gang. After killing the gang, what to do with father and daughter.
A sailor looking for his brother and a traveling show on past murders arrive in Laredo on the same day. A new murder occurs each day with various people implicated including Joe and the sailor whose brother died earlier.
Reese rescues a man and sister during an ambush. Their dying father rewards Reese with an equal share in their land grant - for Laredo County. Parmalee does not trust them while Reese is taught to be a gentleman by Joe and Chad.
Reese's close but eccentric friend is an inventor and mechanical genius. When a group of bank robbers see him open a jammed safe, they decide he should become a member of their gang. To persuade him, they capture and threaten Reese.