From his secret laboratory, Captain Z-Ro and his associates use their time machine, the ZX-99, to learn from the past and plan for the future.

Two prospectors, one the father of Skye "Lightning" Bryce and the other the father of Kate Arnold, find a large gold deposit belonging to an Indian tribe. They head for home but each sends a note to their respective off-springs advising them of their good fortune. One of the fathers conceives a plan of taking a dagger and wrapping a piece of string around the blade, after which he prints on the string with a lead pencil, the exact location of their find. If something happens to them, the string goes to the son and the knife to the daughter. That night an Indian approaches their camp and blows some mysterious wolf powder which causes a man to see wolves in place of human beings. Lightning's father see his partner as a wolf and stabs him to death; later he is brought into town in a dying condition but before dying, hands the knife and the string over to the sheriff with instructions to deliver to Lightning and Kate.

Prof. Millard pretends to be dead and helps Jeff King ferret out Vulcan, the evil traitor at the science academy. Donning his Rocket Man costume King goes from one hair raising rescue to the next in order to keep the newly invented Decimator out of the clutches of Vulcan and his minions.

When some men are attacked by Indians, a survivor obtains an Indian medicine arrow. An Indian tells Blade he has found gold but will not tell him where until he has that arrow. So Blade starts killing the survivors of the attack but fails to get the arrow. One of the men he kills is John Cardigan and Kit Cardigan, a Scout for Custer, now starts looking for the killer of his father.

Two investigators for a stagecoach company are assigned to find out why the company's stages keep being ambushed. They discover that the culprits are white men disguised as Indians, and they set out to discover who is behind the plot.

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.

Rex, a wild stallion, and Rinty, a police dog, are pals. Their master , John Sheldon, is framed for murder, and Alice Ingram plans to race Rex for money to pay for John's legal defense. Meantime, Frank Nolan, who has falsely accused John, sets out to steal Rex for himself.