Bletchley Park: the top-secret landmark of World War Two where a group of young people were fighting to defeat Hitler & win the war. March 1943 the Second World War hangs in the balance & at Bletchley Park a brilliant young codebreaker is facing a double nightmare. The Germans have unaccountably changed their U-boat Enigma code threatening a massive Allied defeat. & as suspicion grows that there may be a spy inside Bletchley Jericho's girlfriend the beautiful & mysterious Claire Romilly suddenly disappears.