Spring, 1941. The Second World War has entered a dangerous phase, with British ships being torpedoed in the Atlantic and nightly bombing raids on major ports. At Bletchley Park, top secret home of the nation's code-breakers, the race is on to crack the German Enigma code and thus prevent further naval and military losses. This endeavour is suddenly very close to home for Frederick Rowlands, blind veteran of the Great War, when his daughter, Margaret,...