Sweden, 1942 - Two old friends meet. They are cousins.
One is Prince George, Duke of Kent, brother of the King of England. The other is Prince Philipp von Hessen, a committed Nazi and close friend of Adolf Hitler. Days later, the Prince George is killed in a plane crash in the north of Scotland.
The official story is that it was an accident - but not everyone is convinced. There is even a suggestion that the Duke's plane was sabotaged, but with no evidence, Cambridge spy Tom Wilde is sent north to discover the truth . . .