Ultra - WW2's Greatest Secret: Battle of the Atlantic

In the darkest days of World War Two, the British Empire is the last major power fighting Nazi Germany. But German U-Boats scour the Atlantic and prey on Allied convoys bringing vital supplies to Britain. To stand any chance of fighting on, British codebreakers at Bletchley Park must crack the elusive Naval Enigma, and fast. Discover this remarkable true story of groundbreaking intelligence work, daring maritime raids and the genius of Alan Turing.