Aircraft are being shot down by a large black plane with a big "X" painted on the wing. The chief suspects are invited for the weekend to an old dark mansion.
Cub reporter Daniel Greely gets a job on a big city newspaper. A string of robberies occur and the owner of the paper blames the police for not rounding up the crooks. Daniel discovers that a coded message in the newspaper's editor's box tips the crooks about each robbery.
The son of a disgraced Olympic decathlete prepares to become a star in his own right. His quest is complicated by a beautiful girl and a bitter rival.
