During the tumultuous period of World War II, Wehrmacht Captain Brandt finds himself overseeing the protection detail of the ousted German Emperor Wilhelm II at Huis Doorn, located near Utrecht in the Netherlands. The German authorities fear that an Allied spy is plotting to assassinate the ex-Kaiser, who, despite lacking any real power, still holds significant symbolic value to the German populace.
As Brandt navigates his duties, he receives explicit instructions from Colonel von Ilsemann to avoid any involvement with the female staff. However, he cannot resist the allure of Mieke de Jong, a maid with whom he embarks on a heated affair. In a moment of vulnerability, Mieke confides in Brandt about her Jewish heritage. To this, he pragmatically responds, > "I'm not," advising her to keep her secret close.
Things take a darker turn when Gestapo Inspector Dietrich warns Brandt of a British secret agent’s presence in a nearby village. Under pressure, Brandt is instructed to uncover another spy hidden within the ex-Kaiser's ranks. When Himmler, the fearsome Reichsführer-SS, is set to visit, tension escalates. Brandt's instincts are piqued when he detects gun oil's distinct smell emanating from Mieke's quarters. His concerns grow as he overhears Mieke discussing her chilling intent to assassinate Himmler with a village pastor, driven by a personal vendetta against the SS for the loss of her father and husband.
As the SS close in on their suspects, the pastor faces extreme torture, pressured to divulge information about Mieke. Meanwhile, Wilhelm's wife Hermine learns about the affair between Brandt and Mieke, expecting repercussions. Yet, the ex-Kaiser, revealing his own past indiscretions, opts to grant them leniency, urging them to maintain discretion.
In a dramatic twist, Brandt, in a bid to shield Mieke, searches her room before Himmler's arrival and discovers the truth about her looming danger. Despite his pleas for her to escape, Mieke resolutely chooses to remain. When Himmler extends a dubious invitation from Adolf Hitler for Wilhelm to reclaim his throne, the atmosphere becomes charged with ambition, especially as Hermine dreams of becoming Empress. Wilhelm, however, is haunted by Himmler’s harrowing remarks about the extermination of disabled children.
Brandt grapples with his sense of duty. In a poignant exchange with von Ilsemann, we are left to ponder, > "First you must decide what is your country and if it even still exists." Mieke, delivering what she believes is a lifeline from Winston Churchill, offers Wilhelm a chance at asylum. But the ex-Kaiser ultimately declines, accepting the reality of his dethronement.
As the Gestapo narrows in on Mieke, Brandt hatches a daring escape plan. Under the pretense of a heart attack, they manage to flee in a van. As tensions rise, Mieke almost succumbs to despair and takes a suicide pill, but Brandt intervenes, eliminating Dietrich in the process. A heart-wrenching moment unfolds as Mieke requests Brandt to join her in flight, fearing for his life, but he remains steadfast, bound by duty. In a fleeting moment, he proposes to her, a promise she accepts before parting ways.
Time passes, and Brandt perseveres in Berlin, where he receives a package containing a book by Nietzsche, a memento from Mieke. The note reveals a London address, suggesting she survived. In London, Mieke awaits a meeting with Churchill, placing her hand on her abdomen, signifying her pregnancy with Brandt's child. Back in Doorn, Colonel von Ilsemann brings good news to Wilhelm, who joyfully realizes Mieke has made it to Britain, marking a glimmer of hope amid the chaos.
