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.

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.

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.

An intrepid reporter and his loyal friend battle a bizarre secret society of criminals known as The Vampires.

The misadventures of a suburban boy, family and friends.