Stephen Neale is recently released from a mental asylum during World War II. He heads to London, hoping for a fresh start. At a village fair, he wins a cake by guessing its weight, a seemingly innocent act that triggers a series of unexpected events. Soon after, Neale finds himself entangled in a web of espionage and intrigue, as the cake appears to be the centerpiece of a Nazi spy ring's covert operations. He narrowly escapes an attempt on his life and realizes that he has stumbled upon something far more sinister than he could have anticipated.

Determined to clear his name and uncover the truth, Neale teams up with siblings Willi and Carla Hilfe. Together, they venture deeper into the shadowy world of counterintelligence. As Neale delves further, he discovers layers of deception, encountering enigmatic figures and puzzling clues that test his resolve and sanity. As the tension escalates and the stakes become increasingly high, Neale must navigate an elaborate maze of danger and betrayal, with each step bringing him closer to unraveling the conspiracy and potentially exposing the spies threatening national security.