Secret Agent X-9

An action-themed movie serial.

The forerunner of all serials, What Happened to Mary was a series of twelve monthly one reel episodes, each a complete entity in itself, revolving its immediate dramatic and melodramatic problems within the framework of a single episode and designed more for story and suspense situations than action.

Only Episode 7, "The Hooded Helper," of this 20-Episode Serial is known to survive. All other episodes are believed to be lost.

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

Dr. Ernst Grood , having already dominated the planet Ergro, now intends to take over the control of the Earth. Unfortunately for him, reporters oppose his sinister designs.

Greedy traders have kidnapped a researcher, hoping he will reveal the location of a treasure in a hidden village. Family and friends of the researcher come looking for him. Adventure ensues.

A team of two-fisted insurance investigators (one of whom disguises himself as The Masked Marvel) endeavor to discover and thwart the loathsome saboteur Sakima.

Congo Bill is hired to locate an heiress lost somewhere in Africa.

A Martian invader crashes his spaceship conveniently close to the workshop of a scientist who is developing an interplanetary craft. If the extraterrestrial Purple Monster can complete the rocket ship and return to Mars, he will be able to start a full-scale invasion of Earth. Good thing Craig Foster sets out to thwart the Monster's mission!

Claire Forrest seeks her kidnapped scientist father, hidden somewhere on Mystery Island. He is held and forced to work on diabolical inventions by Captain Mephisto, a costumed villain.

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.