A military intelligence officer and a pretty reporter try to find a scientist whose inventions can destroy the world.

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.

The Eagle uses sky writing to make threats against a corporation. Nathan Gregory owns a traveling fairground and is thought to be the Eagle. Craig McCoy is a pilot who goes looking for the Eagle when Gregory turns up missing.

An expedition sets off for the last land of Mu, where legend has it that a killer death ray is emitted from the eye of a golden idol.

A wealthy publisher uses a disguise and calls himself the Green Hornet to fight crime in his city.

A mysterious criminal known as The Whispering Shadow commits crimes by means of a gang he controls by television and radio rays. Jack Norton, whose brother was murdered by The Whispering Shadow, suspects that the eerie Professor Strang - whose ghostly wax museum contains figures far too lifelike - may be involved in the crimes.

A madman sets out to destroy a group of Chinatown merchants.