Based around an actual event, this book is set in 1943 inside Britain's code-breaking centre Nazi Germany's U-boats have unexpectedly changed their Enigma cipher and the battle of the Atlantic hangs in the balance In desperation the authorities turn to brilliant young mathematician and codebreaker, Tom Jericho What follows is a frantic race to crack the U-boat code Jericho faces an equally baffling enigma the woman he loves has disappeared and he suspects there might be a spy in the codebreaking centre