One of many great works by E. Phillips Oppenheim, who styled himself as the prince of storytellers, and is credited with creating the rogue male genre of adventure thrillers and was one of the earliest writers of spy fiction from the late 19th and early 20th Century England. The hero in this one is Roger Sloane, a well-off American bon vivant who decides to blow the whistle on a gang of transplanted American gangsters who have abandoned New York and set up a sophisticated crime syndicate on the French Riviera and in Monaco. Robbery, murder, secret hideouts, fast cars, and beautiful women all figure in this tale of roaring 20s. Roger meets a wild and beautiful child of the hills, Jeannine, who reappears as the protege of his Aunt, and the belle of the casino.