Bedelia Carrington, Margaret Lockwood, is newly married and on her honeymoon in Monte Carlo with her husband, Charlie Carrington, in the autumn of 1938. She has a strong aversion to being photographed by him, insisting she is not photogenic. A moment in a sidewalk café changes the tempo: a young painter, Ben Chaney, begins sketching her, and when Bedelia turns her head away, the moment sparks a tense, curious exchange. Ben later encounters Charlie and Bedelia again over drinks, and the spark of suspicion grows as Bedelia claims a pearl ring she wears is a cheap trinket, even though the painter knows otherwise—he had just been speaking to a jeweller when she fetched the ring. The jeweller’s expert had offered a fortune for the flawless black pearl, a clue that gnaws at Ben. Intrigued and uneasy, Ben begins to probe Bedelia’s past, convinced that her fixation with wealth could mask a dangerous pattern: the possible disposal of multiple husbands for insurance money.
Back in England, the tension shifts to the Carrington mansion as Ben is invited to begin a portrait. Carrington falls ill, and Dr McAfee, Julien Mitchell, prescribes rest and orders a private nurse, Nurse Harris, Jill Esmond. Bedelia is told to sleep apart from her husband, while the nurse oversees Charlie’s meals and daily routine. Yet suspicion grows when Ellen, Charlie’s business partner, Ellen Pollock, notices Ben slipping money to the nurse. Ellen worries about what Ben might be up to, and Bedelia’s reaction—especially when Ben hints that a mysterious Edinburgh connection and a hard-to-verify sea captain named Captain McKelvey will soon surface—makes her question what is really going on behind closed doors.
Bedelia’s fear of the nurse leads to a fierce conflict among the household staff: the nurse is dismissed, and Bedelia pushes for even tighter control. She orchestrates for the housekeeper to take an extra day off and visit her cousin, leaving Bedelia and Charlie alone together. She tries to persuade Charlie to flee abroad, arguing that their life would be safer away from business pressures, but he resists, worrying about how they would live if he left his work abruptly. A desperate Bedelia then drives off in a snowstorm, crashes, and is brought home by Charlie. She confesses a fear of not being good enough for him, and he responds with a mix of concern and skepticism about her integrity.
Ben returns later and shares more background stories, presented as stark vignettes within the larger narrative. A Edinburgh chemist named McKelvey, a murdered husband in France, and a Manchester tale about a man called Mr. Jacobs—these fragments are laid out to illuminate Bedelia’s possible temperament and motive. Ben reveals himself as an investigator, convinced that Bedelia is drawn to murder for insurance money. Enraged, Charlie confronts Ben, who leaves, certain he has warned his friend as far as he can. The next morning brings no easy resolution: Bedelia seeks Charlie’s forgiveness, and he seems ready to consider reconciliation, at least on the surface.
The household bustle resumes with the return of the housekeeper, who brings groceries as snow lingers and buses fail. Through a window, Charlie notices Bedelia handling Ben’s groceries; she claims she is simply feeding the family cat, Topaz, whom she dotes on. The sight unsettles him enough to joke about Ben not getting to enjoy his smoked salmon, but Bedelia’s sudden hysteria reveals something darker. A bottle of poison sits in her hand, and Charlie’s mounting suspicion crashes into the moment of truth: Ben’s warnings may have been accurate. Bedelia bolts to her room as Charlie confronts her, insisting she pack, and a chilling dynamic unfolds when he reveals that he will not be leaving with her, but he will not allow her to go alone. In the face of his illness, she attempts to pivot, offering him all her money, only to be rebuffed by his revulsion at its origins. She tries to salvage the situation by claiming illness, and she even arranges for Mary, the housekeeper, to invite Ellen to lunch so Charlie wouldn’t have to eat alone. But when Mary leaves, Bedelia stares down at the poisonous bottle, the danger of her schemes hanging in the air.
