Working undercover, Allen and sidekick Mendoza are out to stop the mail train robberies. Rivers and his gang are the culprits and by joining up with them, they hope to get the evidence they need.

In his film debut Ritter is sent to investigate miners being killed and their mines confiscated. The culprit is Evans and after Tex joins the gang, he is sent to kill two more miners. When Estaban is killed, Tex is put on trial for all three murders.

Kalmus is after the freight contract held by Summers. When his gang kill Summers, Tex and Duke step in to help Madge keep the freight line going. When they foil the gang's further attempts, Kalmus gets the Judge to jail the two.

Hoping to impress a pretty girl he's after, a playboy poses as a newspaperman and goes after a big story.

John Wyatt is a government agent sent to smash a counterfeiting operation near the Mexican border. Joining Doc Carter's medicine show they arrive in the town where Curly Joe, who once framed Carter, resides.