Two cousins meet in a remote castle in Sweden: One is Prince George, brother of the king of England, and the other Prince Philipp von Hesse, a close friend of Adolf Hitler and a committed Nazi. Days later, Prince George is killed in a plane crash and the country weeps, but not everyone believes that it was an accident. The American OSS doesn't believe the story that MI5 are pedaling, so President Franklin Roosevelt dispatches Cambridge don Tom Wilde to uncover the truth—but in this fifth adventure (following Hitler's Secret) what he discovers is far more than he bargained for.