Maurice Gamelin

September 3rd, 1939. Britain and France declare war on Nazi Germany, only two days after the Wehrmacht invades Poland. This day, the sad date when the fate of the world changed forever, the Phoney War began: eight months of uncertainty, preparations, evacuations and skirmishes.

During the worst days of World War II, the British government asks the mathematician Alan Turing to unravel the mysteries of the German Enigma encryption machine, an impossible task to accomplish without the invaluable information that Hans-Thilo Schmidt, a disenchanted but greedy German citizen, had been handing over to the French secret services since 1931.