Two old friends meeting in a remote castle in Sweden. They are cousins.

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.

When FDR, who happens to be a good friend of the prince, hears the tragic news, he wants to find out exactly what happened. The American OSS doesn't believe the story that MI5 are pedalling. The situation is delicate. Professor Tom Wilde, Cambridge don, is called in to uncover the truth--but what he discovers is far more than he bargained for.