Mandrake and his team attempt to prevent "The Wasp" from stealing and using a new Radium invention.
Before the outbreak of WWII, Nazi sympathizers plot to undermine America.
A movie serial in 13 chapters: Some swampland becomes valuable, and various factions squabble over ownership of it.
Jesse James wants to start a new life in a new location, but quickly finds himself wrapped-up in protecting townsfolk from the machinations of evil oilmen.
Dr. Mabuse and his organization of criminals are in the process of completing their latest scheme, a theft of information that will allow Mabuse to make huge profits on the stock exchange. Afterwards, Mabuse disguises himself and attends the Folies Bergères show, where Cara Carozza, the main attraction of the show, passes him information on Mabuse's next intended victim, the young millionaire Edgar Hull. Mabuse then uses psychic manipulation to lure Hull into a card game where he loses heavily. When Police Commissioner von Wenk begins an investigation of this mysterious crime spree, he has little to go on, and he needs to find someone who can help him.
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
Sergeant MacLane of the Mounties investigates the disruptive activities of a bunch of troublemakers.
A new town doctor arrives at the same time as local Indians needprotection from troublemaking looters.
Famed aviator Bruce Gentry is working with scientist Andrew Benson, setting out to uncover the origin of a deadly secret weapon---an electronically controlled flying disc which can be directed at moving or stationary targets. The disc was master-minded by an enemy agent known only as "The Recorder" because...he speaks entirely via recordings. Aided by rancher Frank Farrell and his sister Juanita "Nita" Hodges, Gentry consistently foils "The Recorders" schemes, which are carried out by "The Recorder's" henchmen, Krendon, Allen and Chandler, including an attack on the Panama Canal.
Jerry Blake (aka Federal Operator 99) teams-up with Joyce Kingston to thwart the plans of escaped crime boss Jim Belmont.
Escaped Prisoner 39013 impersonates the rich and influential Horace Granville, allowing him to create a variety of disasters. Fortunately, he is thwarted repeatedly by three daring circus daredevils.
Pulp hero "The Spider" seeks to destroy all criminals. In this serialized adventure, he battles The Octopus, who intends to replace the government of the United States.
A police detective is caught up in a plot to steal two million dollars in bonds.
A serial in 12 chapters. Tarzan goes to Guatemala to find his lost friend, D'Arnot. On the way he helps Major Matling search Mayan ruins for hidden jewels and an idol containing the formula for a powerful explosive. D'Arnot and the idol are rescued, but the idol falls into the clutches of the explorer Raglan.
A mad scientist named Dr. Satan plots to steal key pieces of technology to enable him to build an army of robots based on his prototype to conquer America. The only one standing in his way is Bob Wayne, who fights Satan as the enigmatic Copperhead. Mysterious Doctor Satan is a 1940 film serial named after its chief villain. Doctor Satan's main opponent is the masked mystery man, "The Copperhead", whose secret identity is Bob Wayne, a man searching for justice and revenge on Satan for the death of his step-father. The serial charts the conflict between the two as Bob Wayne pursues Doctor Satan, while the latter completes his plans for world domination.
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
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.
The evil and masked "Gargoyle" is sabotaging all of America's industrial plants. It is up to the Spider to save the country.
The female leader of an international crime ring steals a valuable artifact that can give her the power to control men's minds. Federal agents are dispatched to get it back and stop her evil plans.
Two federal agents battle a gang that hijacks trucks carrying materials vital for the security of the country and sells them to foreign powers.