Transport yourself to the pivotal month of March 1943, where the fate of the war teeters on a precipice. Amidst the hallowed halls of Bletchley Park, a prodigious young codebreaker finds himself ensnared in a twofold nightmare. The Germans have inexplicably altered their U-boat Enigma code, posing an imminent threat of a devastating Allied setback. As tension escalates, casting doubts on the integrity of Bletchley's inner circle, Jericho's world is further shaken when his girlfriend, the captivating and enigmatic Claire Romilly, mysteriously vanishes without a trace.