December, 1932: In the bathroom of a Belgian hotel, a French spymaster photographs secret documents – operating instructions of the cipher machine, Enigma. A few weeks later a mathematician in Warsaw begins to decipher the coded communications of the Third Reich and lay the foundations for the code-breaking operation at Bletchley Park. The co-operation between France, Britain and Poland is given the cover name ‘X, Y & Z’. December, 1942: It is the middle of World War II. The Polish code-breakers are in France on the run from the Gestapo. People who know the Enigma secret are not supposed to be in the combat zone for fear of capture so MI6 devises a plan to exfiltrate them.