During the latter stages of the Civil War, a gang of supposed Confederates, headed by Alex Morel (Lionel Atwill), raid all gold shipments destined for Washington from Oro Grande, California. In the first chapter, "Murder By Accident", Captain Steve Clark (Dennis Moore), is recognized as a Union Secret Service agent by Morel's accomplice Trina Dessard (Virginia Christine), and, with his friend Idaho Jones (Joe Sawyer), is ambushed in the baggage car and sent to almost certain death when the car is un-coupled and plunges down the mountainside. Leaping to safety, in order to be around for the next 12 chapters, Idaho and Steve report to Colonel Sewell (Addison Richards) in Oro Grande, and Idaho introduces himself as a Wells Fargo detective to Cathy Haines (Wanda McKay), the Oro Grande company agent. Steve and Idaho learn that the Morel raiders are only posing as Confederates, and their headquarters are at Morel's "Golden Eagle" saloon. In a raid on the hideout, Steve's brother Jim (Gene Garrick) is killed by the gang. The next victim is Confederate Army Captain Clay Randolph (Regis Toomey) who has discovered that Morel is connected with a group of Prussian spies and gives Steve a clue before he dies. The clue leads Steve to a San Francisco dive owned by Abel Rackerby (Charles Wagenheim), who, thinking he has Steve in his power, exposes the ring's activities and operation methods. Aided by the San Francisco Secret Service, Steve escapes and returns to Oro Grande, where in Chapter 13, "Golden Vengeance", he and Idaho round up the spies.

An expedition sets off for the last land of Mu, where legend has it that a killer death ray is emitted from the eye of a golden idol.

Beyond Hell's Gate Pass is territory controlled by a man who calls himself King Carter; he uses a variety of schemes to prevent the railroad from being built, for fear it will finish his control of (what he considers) his land.

Cowboys and a businessman compete to find lost treasure.  

A 14-episode serial in which Mala, a Polynesian in the employ of U.S. Intelligence investigates sabotage on Clipper Island. A gang of spies causes the eruption of a volcano, for which our hero is blamed. He convinces the local Princess Melani of his innocence and helps her ward off a takeover by rival high priest Porotu.

Strategic targets on Earth are being destroyed by an unknown weapon. Government security head Henderson suspects it's an "atomic ray" originating from the moon! He assigns Commando Cody, scientist and man of action with a secret flying suit, to investigate. Soon, Cody is battling Earth thugs in the pay of Krog the moon man and making trips in his experimental rocket to the moon itself, in a perilous and all but singlehanded effort to thwart the planned invasion of Earth.

Police detectives battle the League of Murdered Men, a gang of resurrected dead criminals.