An introductory newsreel about World War II sets an intense backdrop as D-Day approaches, with the specific date and invasion sites kept under tight wraps. The British Isles are teeming with troops, ships, and supplies, indicating the scale of the impending operation.
The narrative unfolds in London on May 31, 1944, where American Army Major Jefferson Pike enters the Allied Forces Headquarters to discuss preparations for the invasion. Skepticism looms among the high-ranking officials regarding the effectiveness of the Allied deception strategy in fooling the Germans. While examining a map showcasing German troop movements in France, Pike accidentally inflicts a paper cut on himself, an injury that unwittingly becomes significant.
To cover all bases, the High Command dispatches Pike to Lisbon to consult with a German double agent and gauge the situation. Pike raises valid concerns about the dangers of being captured and potentially revealing crucial invasion details under duress, but the higher-ups deem the risk acceptable. As he departs London in civilian clothing, a German spy observes him boarding the aircraft. Not long after, another spy invades Pike's empty hotel room to collect personal belongings, including photographs and hair samples, hinting at a calculated plan.
In Lisbon, Pike arrives at a nightclub for the anticipated meeting with his contact but quickly finds himself in peril when his drink is spiked. Shortly afterward, he wakes up imprisoned in a coffin, disguised as a deceased German embassy clerk, and is transported to Germany. Here, anAmerican-born German Major Walter Gerber, serving as a military psychiatrist, has orchestrated an elaborate deception to extract invasion secrets from Pike. Within a secluded German forest, a faux "American" convalescent center has been created to fool Pike. Major Gerber has a mere 36 hours to glean the invasion plans before the SS intervenes to employ harsher methods.
As Pike regains consciousness, he is thrilled yet perplexed to discover himself among Allied forces. Looking into a mirror, he is taken aback by his unkempt appearance, where gray streaks have invaded his dark hair and his features appear aged. He quickly realizes that he is being closely monitored through a two-way mirror. Moreover, he is manipulated into believing that it is now May 1950 and that the war has long ceased, thus convincing him that he is recovering at an American military hospital in occupied Germany. Both Major Gerber and Anna Hedler, a beautiful nurse, serve crucial roles in this elaborate charade. Various personal items in Pike's room, along with Anna's knowledge about his family, enhance the facade. A rigid system prevents any German being spoken around him, reinforcing the narrative that he is suffering from amnesia following an alleged assault in Lisbon six years earlier.
In a moment of intimacy, Anna claims to have been married to Pike for two months, despite his inability to remember her due to the supposed amnesia. However, he inadvertently reveals significant hints regarding the invasion's location in Normandy during a conversation about the war's final stages. This startling information alarms Anna, who relays it to Major Gerber, who expertly maneuvers to extract vital invasion secrets from the unsuspecting Pike. Time is now of the essence, with the date escalating to June 2.
After a meeting with Major Gerber, Pike unintentionally irritates the paper cut from earlier, prompting a flood of memories, leading to a dawning realization about the ruse. Confronting Anna violently, he ultimately learns that she is complicit in the plot to aid her own escape from a concentration camp. Driven by a desire to undermine their captors, she agrees to help Pike. He instructs her to create a scene, claiming his escape, knowing the Germans will eventually recapture him. However, his actions will now force them to question whether his insights about Normandy were genuine or an act of clever subterfuge.
Disheartened, Major Gerber inquires how Pike unraveled the scheme. Upon hearing about the paper cut, he reflects on the meticulous examination Pike faced upon arrival. Despite Gerber's belief that Pike's mention of Normandy is accurate, it is dismissed by the SS. Consequently, they decide to turn Pike over to the SS, sealing his fate as a likely prisoner of war.
As Major Gerber grows increasingly apprehensive about the repercussions of his failure, he devises a bold plan to ensure his groundbreaking psychological research lives on. He entrusts his papers to Pike and Anna and outlines a daring escape route, aiding them in their flight from captivity.
The clock is ticking as Pike and Anna race against time to flee from their German pursuers, including a relentless SS officer determined to capture them before they reach the safety of the Swiss border. The stakes have never been higher as they fight for their lives and the secrets that could change the course of the war.
