Jerry Blake (aka Federal Operator 99) teams-up with Joyce Kingston to thwart the plans of escaped crime boss Jim Belmont.
Mystery and adventure, surrounding a stolen rubber harvest.
Jim Dorn endeavors to protect Jean McNain from a man she knows has committed a murder, Carter Snowden
Four flying G-Men protect America against enemy spies; one of the four assumes the identity of The Black Falcon, to befuddle the saboteurs even further.
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.
Mandrake and his team attempt to prevent "The Wasp" from stealing and using a new Radium invention.
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.
A movie serial in 13 chapters: Some swampland becomes valuable, and various factions squabble over ownership of it.
Two marine lieutenants battle a masked would-be world conqueror who uses electricity as a weapon.
The obsessive scientist Dr. Miller is working on a matter-transmitter invention called the Paratron; a conspiratorial team of spies and no-goods pursue him to Alaska, trying to steal the device.
Dusty Bates observes some smuggled jewels hidden in a crate aboard a ship; he is pursued by low-lifes when the crate is put ashore.
Tom King Jr. seeks to discover who murdered his father, a Texas Ranger; the trail leads to a network of Axis spies.
Calvin Drake employs a group of low-lifes to drive away land owners along the path of a new railroad; Red Ryder opposes this strategy.
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. His henchmen often kidnap a trained gorilla (the titular "ape") from the zoo, to aid in the schemes.
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.
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 Kent Fowler, who resists the alien plot, without understanding its details.
Beyond Hell's Gate Pass is territory controlled by a man who calls himself King Carter; he uses a variety of schemes to prevent the railroad from being built, for fear it will finish his control of (what he considers) his land.
Prior to the United States' involvement in World War II, the masked vigilante Spy Smasher fights Nazi agents operating within the US, led by the treacherous sabotage leader codenamed The Mask.