Hoppy and his pals arrive in a remote town to investigate the counterfeiting of both U.S. and Mexican money; his only clues are the name "Mordigan" and a drawing of a comet. He quickly finds out that Mordigan is the town "boss"; but what or who is "the comet", and why are Mordigan and his henchmen intent on persecuting a young woman, her drunken brother, and her deathly ill sister-in-law who've also just arrived in town?

Secret Service Major Steel is one of the few men in America aware of the fact that Captain Albright is also Captain Midnight, daring masked aviator dedicated to fighting gangsters and enemies of America.

Henry Courtney, a wealthy importer is found murdered and the famous DeNormand necklace has been stolen. The false testimony of two witnesses, Rand and Hobbs, puts Jim O'Brien in the shadow of the hangman's noose. Martha Courtney, widow of the murdered man and Jim's former sweetheart is convinced he isn't guilty, and promises crooked lawyer Roger Lanning the necklace - which Jim doesn't have - if he can arrange for Jim's escape. Rand and Lanning killed Courtney, but Lanning doesn't know that Rand has the necklace.

A stock broker embezzles a million bucks and plans to take off to Shanghai. A number of obstacles stands in his path, however.

In the future (1970) the US sends a mission to the moon to investigate the building of a moon base.