When the Duke and Duchess of Windsor sailed into Palm Beach, Florida on the SS Berkshire from Nassau on 18th April, 1941, they were looking forward to enjoying three days of relaxation, playing golf, drinking and gossiping with American high society. But unbeknown to this infamous couple, the night before the ship docked, President Roosevelt had instructed FBI chief J Edgar Hoover to launch what was to be an extraordinary covert intelligence exercise that had to fool both the exiled royals and the US secret service agents guarding them. The final FBI report, recently released under the US Freedom of Information Act, running to 227 pags, reveals that the Duke and Duchess of Windsor harbored pro-Nazi sympathies and that Edward was lined up to go back to the throne as a Nazi puppet if Hitler defeated Britain. Now, for the first time, the full, inside story is told, in which Edward and his wife were warmly welcomed by Hitler in Germany and thereafter Edward passed on top secret Allied information to the enemy. It's a tale of treachery, corruption and depravity at the heart of the British monarchy - and one which could have changed the course of history.