A Secret Service agent seeks his missing brother in Africa, and finds his mission complicated by ivory thieves, a girl with a mysterious past, and a troublesome gorilla.

A new town doctor arrives at the same time as local Indians needprotection from troublemaking looters.

Stock-footage from Republic Pictures' earlier Zorro serials was served up once again in this 12 chapter cliffhanger, this time without the financially strapped studio having to credit Zorro creator Johnston McCulley or pay any royalties. Zorro simply became "Don Daredevil" (Ken Curtis), a foppish Easterner by day turned masked avenger by night. Like his not too distant relative, Don wore his disguise in order to battle nasty Roy Barcroft who, under a forged Spanish land grant, attempts to take over the surrounding ranch land.

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.

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

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 operator Bob Whitlock and Irene Blaine. Their journey is aided by Pal, a wolf dog.

Columbia Pictures elevated stunt man Jock O'Mahoney to stardom in this 15 chapter western serial about the building of the transcontinental railroad. O'Mahoney played a railroad agent who uncovers the master criminal behind a series of sabotage attempts on the construction site.

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

The war lords of a potential enemy of the US has the spy ring, led by John Baroda, the Spy King and his aide Nitra, sabotaging the plans for a vast defense system of radar stations along the American borders. Radar Defense Bureau operative Chris Calvert comes to the rescue of a brilliant radar scientist, Joan Hughes, who has been kidnapped by Baroda henchmen in chapter 1 ("The Fatal Fog"), and the two battle together before putting an end to the Spy King in the aptly-named chapter 12, "Day of Reckoning".

The Daily Clarion hires detective story writer Steve Colt to investigate the deaths of a group of scientists working on an atomic rocket development project. Behind the killings is fortune teller Sombra, a spy from an Asian country intent on world domination, who is determined to pilfer the atomic rocket by luring workers from the project to her parlor and killing them with black widow spider venom when they refuse to cooperate.

A young heiress of an American gun factory is threatened by a masked man after her father was murdered. This criminal might be a member of her family or a German agent, who wants to get information about the factory's products, perhaps his mystery has a combined solution - we will probably never know...

On the American frontier in the last decades of the 19th century, Billie is a female cowboy who fights a series of bad men in this film serial.