Mae Webster, immersed in the clandestine world of codebreaking at Bletchley Park, is recruited to help unveil a spy who's on the brink of exposing Britain's most guarded secret: the cracking of the Enigma code. As war rages around her, Mae's life takes an unexpected turn when she falls in love with the enigmatic New Zealand war photographer Jack Knight. Their relationship develops at pace, but tragedy strikes when one of Jack's photographs risks unmasking an elusive double agent.

1989 - Berlin, Germany

Rachel Talbot, a globetrotting photojournalist, ventures into the heart of a fractured Berlin in search of the Stasi officer whom her beloved grandmother Mae blames for betraying their family. Rachel finds herself entangled in the East German uprising and is irresistibly drawn to a charismatic activist. As the Cold War threatens to boil over, Rachel races to expose a traitor before it's too late.