Al Goddard, a detective who works for the United States Postal Inspection Service, is assigned to arrest two criminals who've allegedly murdered a U.S. postal detective.
Postal inspectors track down money stolen from a railroad car.
Postal inspectors investigate a con man who uses the identities of others to falsify credit card purchases. Stealing credit card offers from mail boxes, he obtains cards in others' names, makes many purchases until the card is maxed out, but is always careful to pay minimum balances. According to the story, it is possible for individuals such as this to run many credit cards at a time without being caught.
Charles Starrett makes his final appearance as The Durango Kid, this time as Steve Reynolds, a postal inspector who has gone underground to catch the bad guys. His longtime sidekick, Smiley Burnette appears as an itinerant optometrist who is hardly in the plot line of the film. Jock Mahoney plays Jack Mahoney, an eastern educated dude who has come back home. The Durango Kid teaches Jack how to draw and fire a six-gun, and the two ultimately work together to bring the outlaws to justice.
Postal Inspectors Carson and Underwood have been sent to investigate a series of robberies where both the driver and stagecoach disappear. They team up with Pinkerton agent Bennett who has found some of the stolen money in the possession of Stevens.
Investigators set out to capture a gang of thieves transporting stolen cash through the U.S. mail.
Stolen way back in 1880, a sack of United States mail is discovered in an old attic in 1942. The letters are finally delivered, profoundly affecting the lives of the recipients.
Two newly-appointed postal inspectors, Frank Marshall and 'Slim" Hewitt, set out to track down the sender of a time-bomb to a U. S. Senator and, during their investigation, run across a hooded organization that is terrorizing an American city. They also meet Don Foster, who is loud in his condemnation of the terrorists, and his sister, Nancy, who fears for her brother's life.