There were many moments in World War II when it looked like Hitler’s unshakable faith in Enigma would finally and correctly be shaken. Each time, the Allies must do what they can to keep the ruse alive, to keep the secret safe. How many ships do we allow the U-boats to sink? How many can we save? What kind of defense can we give the city of Coventry, knowing a terrible bombing is coming? What are we willing to sacrifice of ourselves to keep this edge?
