Betrayal and espionage abound as an experimental aircraft is readied for its maiden voyage.

When a friend of Charlie’s is found kicked to death by his own race horse on board a Honolulu-bound liner, the detective discovers foul play and uncovers an international gambling…

The story is told in flashback. Backers want a gambler to marry a rich girl for her dowry.

Charlie’s visit to Paris, ostensibly a vacation, is really a mission to investigate a bond-forgery racket. But his agent, apache dancer Nardi is killed before she can tell him much….

While investigating the theft of antiquities from an ancient tomb excavation , Charlie discovers that the body of the expedition’s leader concealed inside the mummy’s wrappings.