When Professor Marsh disappears while searching for the lost city of Lukachukai, his daughter enlists the help of the Three Mesquiteers.

It is the story of Gene's, a Cavalry scout, who manages to quell an Indian uprising.

Richard Grant, imprisoned in India for a crime he did not commit, escapes and makes his way to Africa.

The arrival of the telegraph put Pony Express riders like John Blair and his pal Smoky out of work. A race will decide whether they or stageline owner Drake get the government mail contract.

Eccentric tycoon Jasper Whyte hosts a dinner at his mansion and announces that he will divide his money and give each guest a million dollars before the stroke of midnight. When his long-lost granddaughter suddenly arrives, Whyte changes his mind and proclaims that she will receive his entire fortune. A second lady appears at the estate, claiming that she is actually Whyte's granddaughter, Doris Waverly, and the first woman is found murdered in her room! With each guest possessing a motive, the mystery of the killer's identity briskly unfolds through a stirring series of surprises.

Crash Corrigan, a recent graduate of Annapolis, and Diana, a go-getting reporter, join Professor Norton for a search for the source of a string of earthquakes, Atlantis. They ride Prof. Norton's rocket submarine searching the sea and little Billy Norton, the professor's son stows away, of course. When they find Atlantis they are caught in a war between peaceful Atlanteans, note their white capes, and war-monging Atlanteans, note their black capes. After many harrowing moments for Crash, Diana, Prof. Norton and Billy, they barely get away with their lives when they escape a tower of Atlantis raised to the surface for the sole purpose of dominating or destroying the Earth (Which one depends on the compliance of the upper world dwellers.)

The Wrecker wrecks trains on the L & R Railroad. One of his victims is Larry Baker's father. Baker wants to find the evildoer, among a host of suspects, but it will be difficult since the Wrecker can disguise himself to look like almost anyone

Ellery Queen solves a mystery involving a valuable stamp.

In this Western, comprised of 12 chapters from a serial, Kit leads a group carrying a large gold shipment across the wild West. When the Mystery Riders attack and steal the gold, Kit is the only survivor. He later joins forces with the cavalry to retrieve it.

As the sheriff of a small western town, Autry sings his way into a relationship with Eleanor, a singer from a Chicago nightclub who earlier witnessed a murder.