In Los Angeles, California, opera singer Joan Spruance is going through a divorce with her husband, Lewie Duart. When she returns home to find that her apartment has been broken into, she tells police that Lewie, who is also her choral conductor, would have no reason to commit the crime. Joan’s sister, Antonia “Andy” Ellerman, arrives during the investigation, and asks if Joan received the manuscript she sent her. Andy reveals she has written a story about her former billionaire boyfriend, Redmond “Red” Layls, whose business practices are questionable. Joan warns her against writing the exposé, but Andy insists on meeting a publisher in New York City. When Joan frets about her safety following the break-in, Andy offers to let her stay at her home while she is away. Elsewhere, guard dog trainer Harry Bliss attends a counseling session with his estranged wife, Adele. She is angry that he mistreats her and owes her several months’ rent on an office space. At work, Harry dodges several bill collectors and has his secretary lie about his whereabouts. Joan stays at her sister’s gated Hollywood Hills home, but worries when Andy’s live-in housekeeper, Socorro, also leaves for vacation. Alone in the house, Joan decides to get an dog for protection, and telephones Harry’s company, House of Bliss Guard Dogs. He arrives with a German Shepherd, “Duke,” and teaches the commands to Joan. At choral practice, Joan’s friend, Eddy Revere, offers consolation, and wonders why she no longer confides in him. Sometime later, Harry returns for more dog training. When Joan breaks down in tears, he invites her to dinner. Harry shares that he has been divorced for eight years, and he and Joan flirt. Intoxicated, Joan invites Harry to one of her concerts. In time, Harry is visited by Red Layls’s attorney, Laurence Moncrief, who asks him to steal the incriminating manuscript from Joan. When Harry refuses, Moncrief calls him by his real name, “Eugene Earl Axline,” and threatens to reveal he is living under a false identity to avoid creditors and the Internal Revenue Service (IRS). Before leaving, he gives Harry a check for $15,000 to obtain the manuscript. Joan receives a death threat in her sister’s mail, and her former husband, Lewie, asks her to move back home with him. Joan dismisses him and reveals she is seeing someone else. Later, she invites Harry over for dinner and receives a frantic telephone call from her sister, who reveals that Red kidnapped her to prevent her book from being published. Andy had gone to a hospital to have a bone spur removed before leaving for New York, but while there, Red had her drugged and abducted. She woke up in an unknown hospital. Harry offers to help Joan locate her sister, and she searches Andy’s house for the missing manuscript. Harry prepares to mail the payoff check back to Red’s attorney, but changes his mind at the last moment, and returns to Andy’s home to look for the document. When he finds a present Joan bought for him with a letter professing her love, he feels guilty. Sometime later, Joan’s friend, Helen Dextra, comes to visit as Joan fills out a “missing persons” police report for her sister. Joan prepares to drive Helen home, but a masked assailant wielding an axe attacks them in the garage. With the guard dog locked in the house, Joan fends for herself, beating their attacker with a wooden stick. As the intruder chokes her, Helen comes to her rescue. Joan bites the man’s hand and beats him until he flees. Later, Harry chastises Joan for not having Duke by her side, but they make love. In time, Joan gives him a wristwatch, and he is touched by the gift. Harry tries to admit his connection to Red Layls, but she interrupts him to watch a television news report about her sister’s disappearance. The story reveals that Red is being treated for a minor illness at a hospital, prompting Joan to search the same facility for her sister. Harry tries to stop her, but reluctantly goes along. After arriving, they steal lab coats, pretend to be doctors, and are directed to Andy’s room. Joan dresses her sister in her own clothes, and Andy leaves through the front door with Harry, while Joan stays behind in a hospital gown. While Andy waits outside, Harry returns for Joan, but he is locked out as Red’s men arrive. When Andy sees Red step out of his limousine, she verbally attacks him for kidnapping her. Meanwhile, Laurence Moncrief visits Andy’s room to get her to sign legal papers that would protect Red’s innocence, and is surprised to see Joan under the covers. As Harry shouts up to his lover, Moncrief reveals that Harry works for him. Joan is stunned, but Harry rips up the $15,000 check. Andy returns to her hospital room and tells her sister that Red tearfully professed his love for her. Joan chastises her sister for forgiving him. Red and Harry attempt to sort out their differences, and Red denies responsibility for the attacks on Joan. Although Harry begs Moncrief to defend him, his lie is exposed, and Joan learns he is still married. On their drive home, Harry explains that his marriage was a mistake and begs for forgiveness, but Joan ends their relationship. After a dress rehearsal for an upcoming concert, Joan accepts a ride from her friend, Eddy Revere, and Harry follows. In his car, Eddy expresses anger that Joan rebuffed his advances years before, and Joan notices the bite mark on his hand, realizing he is her attacker. On a dirt road, Harry’s van gets stuck, and Eddy drives to a remote hillside. Joan pretends to be sympathetic, but plans her escape. When she tries to flee, Eddy lunges at her. However, Harry comes to her rescue. Eddy pulls a knife on Harry, and the men tumble down the hill. On the cliff side, Harry knocks Eddy unconscious. As police helicopters hover overhead, Harry criticizes Joan for her choice of friends, and Joan throws rocks at him. Finally, Harry professes his love, and reveals that his real name is Eugene. Joan forgives Harry and kisses him. The next night, Harry attends Joan’s concert with a large bouquet of flowers.