In the Dutch city of Groningen, Claude Rains stars as Kees Popinga, a dedicated chief clerk and bookkeeper for an esteemed 300-year-old trading company managed by Herbert Lom as Julius de Koster Jr. Kees leads a modest, routine life; he's passionate about trains but has never ventured beyond Amsterdam, living comfortably in his predictable world.
This calm is disrupted when a man named Merkemans, portrayed by Felix Aylmer, approaches de Koster seeking employment. Merkemans, who had once managed a company destroyed by embezzlement, is turned away due to his connection to the scandal, reflecting de Koster’s desire to maintain the company's spotless reputation. During these events, a French police inspector named Lucas, played by Marius Goring, arrives with suspicions about Dutch money illegally circulating in Paris, hinting that de Koster’s firm might be involved. De Koster invites Kees to assist in demonstrating that the company’s books are untouched, which seems to be a straightforward vetting process.
One evening, Kees observes de Koster sharing an intimate moment at a station with a woman, played by Märta Torén, which sparks his curiosity. As the investigation unfolds, Lucas confronts both Kees and de Koster with photographs of the woman, raising questions about her identity and the nature of their relationship. De Koster, under pressure, lies, while Kees defends him, showing trust in his employer—even though doubts begin to grow.
Later, Kees finds himself witnessing de Koster burning the company’s books in the dead of night, revealing an attempt to hide financial irregularities. De Koster then claims the firm will go bankrupt in the morning, and Kees’s suspicions deepen. That night, he follows de Koster to a canal, where the latter presents a fake suicide note, hinting at his intent to end his life. Kees intervenes, trying to prevent de Koster from jumping into the water, only to discover that the note was fabricated. When de Koster’s briefcase spills open, Kees is shocked to find 100,000 Dutch guilders in cash—evidence of black money—along with a train ticket to Paris and the woman's address.
Deciding to act on impulse, Kees takes the briefcase and boards the train to Paris, abandoning his family life in the process. On the train, he unexpectedly encounters Lucas, who makes it clear he suspects Kees. Fearing trouble, Kees jumps off before reaching Paris. He soon seeks out Michele Rozier, the woman seen earlier, but she dismisses him, unaware that he has the money. Lucas later explains to Michele that de Koster is alive and involved in criminal activities, though Kees himself remains in the dark about his employer's fate. Lucas worries Kees might turn to desperation, given the precarious situation.
Motivated by Michele’s desire to claim the money, she begins tracing Kees, leading to a tense pursuit. However, she cooperates with the police, helping them locate Kees. She then introduces him to Louis, her lover, who resides near train tracks and promises to help Kees obtain false papers so he can escape the country. Suspicious and desperate, Kees hides the money in an abandoned car nearby, wary of Louis’s intentions. His boredom and frustration with his mundane life grow, and he begins to live dangerously by taking Michele out on the town, where he starts to trust her more.
As Kees becomes more infatuated with Michele and the thrill of danger, he drunkenly confesses his plans to Lucas and reveals the location of the money. Michele, driven by her desire for wealth, retrieves the cash—only to be caught by Lucas, who offers her immunity if she helps apprehend Kees. Defying the police, Kees steals a knife from a shop window and confronts Michele at Louis’s garage, where an intense showdown ensues.
In a dramatic climax, Kees threatens Michele with the knife, insisting he will prove himself by killing her. However, his resolve falters, and he ends up murdering her in a fit of rage. Fleeing in chaos, Kees runs onto the train tracks, risking his life as an approaching train speeds toward him. Miraculously, the train switches tracks at the last moment, and Kees, delirious and overwhelmed, stumbles toward the train. Marius Goring as Lucas manages to arrest Kees just before tragedy strikes, sealing his fate.
This story is a gripping portrayal of a man entangled in a web of crime, deception, and personal despair, illustrating how a seemingly simple life can unravel under the weight of greed and secrets.
