George Dumurrier is a wealthy yet self-absorbed doctor living in San Francisco who manages a clinic alongside his younger brother, Henry. Despite his bustling professional life, George's personal life is marked by complications: he has left his wife Susan, who suffers from asthma, in the care of her sister Marta and a local nurse, instead of attending to her himself. His own romantic interests include Jane, the personal assistant to a trendy photographer named Larry, with whom George is engaged in a passionate affair. Jane, portrayed as deeply in love with George, harbors a sense of fatalism about their future together, sensing that obstacles may stand in their way.
The story takes a turn when George and Jane decide to escape their daily routines with a romantic trip to Reno, known for its casinos and vibrant nightlife. Their getaway begins with hope and anticipation but quickly turns grim after George receives shocking news from Henry. He learns that Susan has died suddenly during a violent asthma attack, prompting their immediate return to San Francisco. Upon their return, George finds himself received with mixed emotions—Henry offers him comfort, but Marta greets him with hostility, reflecting her disapproval of his marriage to her sister.
This tragedy coincides with the revelation of a lucrative life insurance policy valued at a million dollars, left behind by Susan. The policy becomes a significant point in the narrative, especially as George's entrepreneurial ventures grow more reckless. An insurance agent, suspicious of George's activities, begins to follow him. His suspicions escalate when he uncovers George's affair with Jane and passes this information to Detective Inspector Wald.
In a quest that mixes elements of detection and psychological intrigue, George and Jane stumble upon an unexpected discovery at a strip club called The Roaring Twenties. There, they encounter Monica, a striking blonde stripper who bears an uncanny resemblance to Susan. George becomes morbidly fascinated with her, and his feelings quickly morph into an affair fueled by both obsession and curiosity. Monica's appearance triggers a series of events, as she claims to have been paid by a woman calling herself Betty to impersonate Susan, attempting to manipulate the situation.
As the police begin to investigate Monica further, they find her involved with high-class prostitution and a wealthy client, Benjamin Wormser. Marisa Mell portrays Monica, who toys with her admirers, revealing her complex and manipulative personality. Benjamin Wormser, played by Riccardo Cucciolla, arrives at the police station with an enormous bail for Monica, who has already been released through an unknown benefactor, sparking suspicion and intrigue surrounding her true motives.
A search of Monica’s apartment uncovers an envelope with money, and when police find George’s fingerprints on it, he is suddenly charged with his wife’s murder—an accusation that throws his entire life into chaos. As the case unfolds, Monica vanishes, leaving George grappling with his mounting doubts and desperation. He is tried, convicted, and sentenced to death, a fate that seems sealed as the evidence against him piles up despite his pleas of innocence.
However, the critical turning point occurs months later when Henry visits George in prison and confesses a shocking truth: the entire plot was a deception orchestrated by Henry and Susan to eliminate George and claim the insurance money. Monica had actually been Susan all along, who faked her death to frame her husband. This revelation shakes George to his core, yet he’s unable to persuade his lawyer to seek a stay of execution before his scheduled death in the gas chamber.
In his final moments, only Jane maintains her belief in George’s innocence, while Larry (the photographer's assistant) and others remain silent or restrained. As George faces his execution, a last-minute intervention occurs. A phone call from the governor halts the proceedings, triggered by a telex from the FBI. The message reveals that Susan and Henry were actually shot dead in a cafe in Paris by Benjamin Wormser, the jealous and spurned lover, exposing the truth behind the elaborate deception.
This intricate web of lies, obsession, and betrayal ultimately unravels with a tragic and ironic twist, leaving viewers contemplating the perilous boundary between appearance and reality, and the devastating consequences of greed and deception.
