A 14-episode serial in which Mala, a Polynesian in the employ of U.S. Intelligence investigates sabotage on Clipper Island. A gang of spies causes the eruption of a volcano, for which our hero is blamed. He convinces the local Princess Melani of his innocence and helps her ward off a takeover by rival high priest Porotu.

When his father is killed in a train wreck, Larry Baker vows to unmask a mysterious criminal called "The Wrecker," who has targeted the L&M Railroad for deadly" accidents."

An intrepid reporter and his loyal friend battle a bizarre secret society of criminals known as The Vampires.

A newspaper publisher and his Korean servant fight crime as vigilantes who pose as a notorious masked gangster and his aide.

A gambling ring run out of the Mogul Taxi company is intent on fixing college football games. Football star Harold "Red" Grange is a target for the gamblers, whose thugs try to eliminate Grange from playing. Grange's buddy Buddy is himself vulnerable to blackmail, since he has broken team rules by marrying. The crooks use all their wiles to keep Grange and Buddy from leading their team to victory.

Mandrake and his assistant Lothar are working the cruise lines and make the acquaintance of Professor Houston who has developed a radium energy machine, which is much coveted by a masked Crime Lord known as "The Wasp".