Although under tight police escort, nervous hoodlum Pete Tonelli, the state’s chief witness against Mafia head Ben Costain, is killed by an assassin upon arriving at the court house to testify. Shortly thereafter, cynical police lieutenant Vince Striker visits the women’s prison to pick up Sherry Conley, a former model who knew Tonelli. To Sherry’s consternation, Vince signs her out of prison and without further explanation takes her, with prison police escort Mrs. Willoughby, to a heavily guarded hotel. There Vince introduces Sherry to District Attorney Lloyd Hallett, who explains that he and the police have been working for two years to try and deport the foreign-born Costain, as it has been impossible to link him to more serious crimes. Although Sherry was present with Tonelli onboard Costain’s yacht on a trip to various West Indies islands and can identify another criminal boss that Costain brought into the United States illegally, she balks at Lloyd’s request that she become the state’s new chief witness. When Lloyd promises Sherry protection and several perks in order to gain her trust, Vince, convinced of Sherry’s inherent dishonesty, departs in disgust. Sherry dismisses Lloyd’s argument of having a social obligation to testify, citing instead her fear of Costain and Tonelli’s murder. Lloyd decides to ask the state governor to commute the remaining eleven months of Sherry’s five-year sentence on an accessory conviction and instructs Vince to work on winning over Sherry. Despite his belief that Sherry is hopelessly corrupt, Vince half-heartedly complies, grudgingly listening to her explanation that her difficult childhood led to her taking up modeling at the age of sixteen. Meanwhile, Costain’s lawyer, Marvin Rickles, visits Lloyd and demands to know the identity of the state’s new witness, before the district attorney angrily throws him out. After Sherry enjoys an enormous meal provided by room-service, she asks Willoughby for advice, and the policewoman echoes Lloyd’s earlier refrain about having a social obligation to testify, but Sherry remains unconvinced. Later, Lloyd telephones Vince to report that the governor has agreed to commute Sherry’s sentence if she agrees to testify. Unexpectedly warming to Sherry’s brashly affable personality, Vince asks her more questions and she explains that she was never more than acquaintances with Tonelli, but that being best friends with his sister brought her in contact with him. Sherry asks to play the radio and then talks Vince into dancing with her, but moments later the couple is shot at through the window. Before Vince kills the attacker, Sherry is grazed in the arm as Willoughby whisks her into the back room. When Lloyd arrives moments later, he finds Sherry hysterical with fear as a doctor tends to her. Unknown to all, Willoughby has also been injured and Sherry is dismayed when the policewoman collapses. Vince argues that Sherry should have been taken directly to the town jail, but Lloyd now suspects it will be too dangerous to transfer her. The following morning, Vince presents Sherry with a new dress, but she suspects it is bribery from Lloyd and still refuses to testify. Later, Sherry is touched when she realizes the dress is a sincere gift from Vince. Having discovered that Sherry has a sister, Clara Moran, living nearby, Lloyd arranges to bring her to see Sherry, but the sisters fight bitterly and Sherry is more determined than ever not to testify. Vince, taking a brief break to go home to shower, is picked up by Costain’s men and taken to the mafia boss, who chastises him for killing the assassin the night before. Vince, who has secretly been on Costain’s payroll for over a decade, explains he had no choice and tells Costain that he does not believe Sherry will testify. Costain, who has learned from a spy inside police headquarters that they intend to transfer Sherry to the county jail the night before court convenes, nevertheless convinces Vince to unlock Sherry’s hotel bathroom window just before the transfer that night. Back at the hotel, Sherry angrily explains to Lloyd that Clara never took responsibility for her as a child and he attempts to point out her current responsibility to testify, but Sherry again refuses. Just before Lloyd’s arrival, the district attorney learns from police headquarters that Sherry will be transferred, but is surprised moments later when Vince inadvertently reveals he already knows about the transfer. Their discussion is interrupted by a call informing Lloyd that Willoughby has died, which disturbs, then angers Sherry, who then abruptly declares that she will testify. Later that evening, an increasingly tense Vince attempts to talk Sherry out of testifying, then reluctantly pretends to check the room’s windows, leaving the bathroom window unlocked. As the time for the transfer approaches, Vince grows increasingly anxious and when a noise comes from Sherry’s bedroom, he rushes inside in time to shoot the assassin, but is also killed by him. When another detective reports that the window was unlocked from the inside, Lloyd and Sherry sadly realize Vince’s involvement with Costain. The following day, to Costain’s dismay, Sherry appears in court and testifies against him.