Mystery of the Riverboat

An escaped criminal impersonates a Police Commissioner, causing no end of trouble to a determined Federal Agent.

A famous scientist invents a humanoid robot (the titular "monster"), so a greedy rival scientist plans to steal it for use in his criminal plans. ...

Two marine lieutenants battle a masked would-be world conqueror who uses electricity as a weapon.

Two British officers are assigned to collect information to convict Captain Kidd of piracy.

Mota is a Martian representative, who has come to impose interplanetary law on the Earth (which has become too dangerous); opposing his authority is...

Government agents try to thwart smugglers, while some sort of plot unfolds, about a hidden treasure revealed by cursed coins.

Government agents work to interfere with schemes to trick the Comanches into war with the Texans.

Before the outbreak of WWII, Nazi sympathizers plot to undermine America.

The story of a boy, a dog, and a man. The boy discovers he is heir to a shipping line, and travels to Los Angeles, accompanied by inventor/radio...

Sergeant MacLane of the Mounties investigates the disruptive activities of a bunch of troublemakers.

An Indian rug is the key to the location of a lost treasure. When the rug's owner is murdered, it becomes a case for Forest Ranger Steve King

The Phantom Rider helps Mary Grayson thwart a plot to steal her land.