The Mystery of Marie Roget

In 1889 Paris, Marie Roget has been missing for ten days. Police inspector Gobelin takes the case, but his superiors threaten to pull it from him. He brings medical officer Dr. Paul Dupin to assist, hoping a fresh perspective will spur progress.

The body of a dead woman is recovered from the river. Despite the mutilated face, Minister Beauvais claims it could be Marie. When Marie suddenly returns, she refuses to disclose where she has been all this time.

Camille becomes engaged to Marcel Vigneauz. Unbeknownst to Camille, Marie and Marcel are lovers scheming to murder Camille for the inheritance Cecile Roget stands to gain. The plan is illegal and perilous, setting up a deadly confrontation.

Cecile Roget asks Dupin to escort Camille to a social gathering, fearing that the party could be the scene of a future murder. Dupin agrees to oversee Camille’s safety and uncover hidden agendas. The arrangement brings the inspector and the doctor into closer contact with the family.

At the party, Beauvais declares his knowledge of Marie's affair with Marcel and presses her for an admission. Marie and Marcel argue, with Marcel hesitating to murder Camille, revealing a torn loyalty that complicates their plan. The social setting becomes a pressure cooker for hidden motives.

Marie vanishes once more, and a second body, a faceless woman, is discovered. The evidence points toward a continuous deadly scheme surrounding Camille’s future fortune. Dupin and Gobelin sense the danger intensifying as the investigation narrows.

Dupin infiltrates the morgue to remove the brain from the second body and uses forensic reasoning to identify it as Marie. This gruesome discovery confirms the killer’s proximity and forces the case into sharper focus. The realization raises the stakes for everyone involved.

Cecile Roget confides in Camille that Marie intended to kill her, foreshadowing the danger Camille faces. The revelation adds motive and urgency to protect Camille, heightening the tension within the Roget family. Camille’s trust in those around her becomes increasingly fragile.

Marcel admits killing Marie, claiming he did so to save Camille. Beauvais then demands the charges against Marcel be dropped, a demand Dupin reluctantly agrees to, signaling a shift in the investigation. The confession complicates the moral accounting of the case.

Following the confession, Marcel challenges Dupin to a duel, and Gobelin learns from Scotland Yard that the first dead body was Marcel's English wife. The two men disappear, creating an atmosphere of pursuit and threat as the web tightens. Dupin prepares for a confrontation that could expose deeper plots.

Dupin and Gobelin realize that Dupin had manipulated the case by accusing Camille of possessing a non-existent diary, ensuring the killer would retrieve it. The ruse exposes Dupin’s calculated strategy to trap the murderer. They hurry to the Roget home where the final confrontation unfolds.

The investigators arrive just as Marcel is about to kill Camille. Gobelin shoots Marcel to prevent the murder, and the case culminates with the revelation that Beauvais had secretly aided Dupin. The complex plot is unraveled, and Camille’s safety is secured, though the truth about the conspirators remains bitter.