Rita Kendrick emerges from the surf on a beach in La Paz, Mexico, and discovers a stranger, Dave Arnold, lingering nearby. After a brief but intense flirtation, Dave kisses Rita. Although she initially resists him, Rita agrees to meet Dave later on his boat. That night, Rita and Dave swiftly fall in love, although Rita, who is bent on becoming wealthy, surmises that Dave is but a humble fishing boat operator. Rita leaves hastily and meets drunken Harley Kendrick and his supposed friend, Larry Chalmers, at a café. When Dave happens into the same café and assumes that the older Kendrick is Rita's father, Kendrick, who is posing as her abusive husband, slaps Rita for her rude introduction, and Dave retaliates by striking him back. Kendrick, Rita and Larry then return to Kendrick's yacht. Larry believes Kendrick is asleep and, unaware that Kendrick and Rita are setting him up for blackmail, offers Rita money to forsake Kendrick. Rita feigns interest, but when Larry is gone, Kendrick demands information about Dave. Dissatisfied with Rita's response, Kendrick threatens to expose her to the police as his shill if she tries to leave him. Rita meets with Dave the next afternoon and confesses that Kendrick, whom she loathes, is not her husband but her boss in blackmail schemes, and convinces Dave she wants to leave Kendrick for him. Although he is shocked, Dave is unable to resist Rita's allure. Later, Kendrick tells Rita that Larry fell for his ruse as a shattered husband and paid $25,000 for his silence. Rita demands her share, but Kendrick withholds the money, and they leave La Paz for Balboa Island in California. Having received a message from Rita about her new location, Dave sells his boat and goes into a business partnership with his fisherman friend, Tony Margoli, in Balboa. One night, Dave urges Rita to leave Kendrick, and she admits that it is difficult because she is obsessed with being rich due to her impoverished childhood. She then suggests to a horrified Dave that they kill Kendrick so she can inherit his money. Unknown to them, Kendrick has hired private investigator J. J. McGonigle to follow them and report their activities. When Rita announces to Kendrick that she is leaving him for Dave, he ridicules her and bloodies her cheek after she slaps him. Rita moves to a hotel in San Pedro and calls Dave, who is infuriated to discover her black eye. When Kendrick later offers Dave $10,000 to disappear, Dave takes the cash and declares it belongs to Rita. He then slaps Kendrick several times and warns him not to return. Dave finally confronts McGonigle, who has been following him, and offers to pay off the investigator. However, McGonigle rejects the bribe and advises Dave to leave Rita for his own safety. Dave nevertheless returns to Rita's hotel room and discovers that she has purchased dynamite and electrical charges with which she plans to blow-up Kendrick on his boat. Dave opposes her plan, protesting that he is morally opposed to murder. Dave offers her Kendricks' bribe and tells her about McGonigle, then urges Rita to flee with him. McGonigle, meanwhile, shows Kendrick surveillance photos of Rita purchasing the dynamite. Later, Rita and Dave are picked up by police detectives and interviewed by homicide captain Getz. Getz and Jerry Jannings, from the District Attorney's office, reveal that Kendrick, a known embezzler and blackmailer whose real name is Harold King, died when his yacht exploded in a channel. However, McGonigle provided an alibi for them because of his surveillance. A shaken Rita and Dave are released but are later approached by McGonigle, who demands a meeting. That night at his office, McGonigle reveals that Kendrick planned his own death to frame Rita and Dave for murder, and although Kendrick's body has not been found, he is presumed dead. McGonigle now barters the $10,000 in exchange for negatives that show Rita buying the dynamite, and advises that Rita's inheritance blew up with the boat. Dave urges a resentful Rita to give him the money, after which they leave, but Rita insists on going home alone. Unknown to Dave, she returns to McGonigle's office to demand her money back. McGonigle tries to interest Rita in a new partnership with him, but she shoots him after he makes unwelcome sexual advances. However, Rita is unable to retrieve the confession McGonigle addressed to Getz that dropped into a mail chute. Rita later confesses to Dave that she killed McGonigle and they flee to La Paz, where they are married. After Rita leaves their hotel room to buy Dave a wedding present, she is stunned when Kendrick approaches her and forces her to accompany him to his new yacht. There, Kendrick admits that he would not have made his presence known if she had not killed McGonigle, which now makes her vulnerable. Rita appears to be resigned to Kendrick's plan to travel together to South America, where there is no extradition, but when she lures the desperate Kendrick to come closer for a kiss, she shoots him. Rita then drops the gun on the deck and leaves Kendrick for dead. She returns to the hotel and, with forced cheerfulness, asks Dave to take her to the beach where they first met. There, she admits to shooting Kendrick and tells Dave that she has wired Getz to come and arrest her, because she wants to prevent ruining Dave's life further. They are both surprised when Kendrick, who is still alive, calls out to them from a nearby palm tree. Dave approaches him, intending to protect Rita, but Kendrick shoots and injures Dave, then mortally wounds Rita before dying. Rita reveals her genuine love for Dave and dies in his embrace.