Sworn to Secrecy

June, 1940. England stands alone against brutal aggression. The Germans have yet to be stopped in their lightning thrust across Europe. The British are outnumbered, but they have a secret weapon four years in the making. There were only 500 RAF fighter pilots in the Battle of Britain, but behind them, deep in the shadows of war, over 10,000 special men and women fought the battle of "Ultra".