Unemployed writer Alton Bennet tells psychiatrist Dr. Redman about his nightmares, in which he dreams that he murders his wealthy wife Ruth with a heavy perfume bottle. Redman's secretary, Merl Kramer, takes notes as Bennet denies coveting his wife's jewels, which are worth $100,000. After Bennet is refused an advance from his publishers, he becomes jealous of Ruth's close relationship with handsome young architect Guy Bayard, who is designing their new beach house. That night, Merl gently rebuffs the unwanted advances of her boardinghouse neighbor, private detective Karl Benson, whom she considers only a friend. After Merl tells Karl about Bennet's case, Karl steals her office keys and has Charlie, an unscrupulous locksmith and fence, duplicate them. Karl then accompanies Merl to her office for Redman's evening appointment with Ruth. When Karl sees bejewelled Ruth enter Redman's building with Bayard, he copies her address from her car registration. The next day, Karl brings Ruth's jewels to Charlie, but Charlie accepts only the smaller pieces as he fears the larger ones would be connected with Ruth's murder, which has just been reported. Karl then asks Merl to deposit his money in her bank account for safekeeping, and hides Ruth's jewels in his apartment. When homicide detective Lieut. Dawson arrives at the Bennet apartment to investigate Ruth's murder, he discovers that insurance investigator Joe Cooper is already on the scene. Although the perfume bottle is determined to be the murder weapon, Bennet vehemently denies having killed his wife, and his butler affirms that he had been incapacitated due to a large quantity of sleeping pills. As the investigation proceeds, Joe precedes Dawson in questioning suspects, including Merl, who became a suspect when Redman's files on Bennet were found missing, and Dawson learned that she forged her letters of recommendation. Joe believes that Merl is innocent, although she refuses to explain why she left California, where her daughter still lives. Hoping to put Dawson and Joe off, Karl investigates the murder, claiming that he is interested in the insurance company's reward for the recovery of Ruth's jewels. Karl then plants one of Ruth's rings in Merl's upholstered chairs, and when police later find the ring at a pawn broker, they trace it back to Merl. Joe takes Merl out to dinner and learns that Bennet and Karl were the only persons in her apartment before she found the ring. Police arrest Merl after Karl shows them her bank book, which reflects a $1,000 balance. When Karl is confronted by Redman, who confesses to being Ruth's killer, Karl explains that he had also intended to frame Bennet for his wife's murder and steal her jewels, but as Redman got to her first, Karl knocked Redman out and stole the jewels from him. Karl now insists that they work together and split the reward. Merl, meanwhile, is interrogated by police, and Dawson orders Karl to search her apartment. Karl murders Redman, then plants the jewels in Merl's chair. After Merl is released, Karl forces her to pull the jewels out of her chair, and she realizes that she has been framed. Karl knocks her out and intends to throw her from the roof, but her awakening screams draw the police, and Karl pretends that he was attempting to prevent her from committing suicide. Back in Merl's apartment, Dawson brings in eyewitnesses who identify Karl as having been at the Bennets' apartment on the night of the murder. Karl is arrested, and later, Joe invites Merl to dinner.