An artist suffering from mental problems from his experiences during the war goes to Acapulco on his honeymoon. Soon young women are turning up dead in the area, and the ex-GI comes to believe he might be responsible, as he has long stretches where he can't remember anything.

Since their marriage six months previous, Trevor and Stella Stevenson have been drifting from one exotic locale to another, searching for subjects for Trevor, an artist, to paint, while living off his small inheritance and the money he makes selling paintings. Stella, who met Trevor at a gallery where she worked, is completely devoted to him, having experienced happiness and contentment that she has never known before. After traveling in uncomfortable accommodations in a banana boat, they arrive in Acapulco and take a cottage at a pension owned by Señora Reidl. On the first night, weary from their travels, Stella goes straight to bed, while Trevor, whose migraines have been induced by the pounding of pistons under their cabin in the boat, decides to swim at the beach. On his way, he sees a waitress at the cantina and asks her to pose for him. Assuming he is really asking for sexual favors, she leads him to her house. Later, she is found dead. As Trevor was the last person seen with her, he is questioned by Capt. Henrique Monteros, a passionate, gallant widower and the nephew of Señora Reidl. To protect Stella from what looks like infidelity, Trevor lies to Monteros about some details of that night, failing to mention that he went to the woman's house, but shows him the sketches he made that evening. Although respectful toward the Americans, especially Stella, Monteros senses he should investigate further. Through inquiries, he learns that Trevor, a World War II Purple Heart medal recipient, was hospitalized for shell shock and amnesia prior to his marriage. When he questions the loyal Stella about Trevor's illness, she pretends she knew about it, although, in reality, he never mentioned it. Later, she encourages Trevor to be completely honest with her and he explains that he delayed telling her about his trauma, because he feared losing her love. The husband of the waitress, prizefighter Amigo Herrera, discovers more sketches by Trevor in his home and uses them to blackmail him, via his lover Maria, Señora Reidl's maid. Trevor then confesses to Stella that he did go to the woman's house that night, but claims he did nothing more than draw her. After some discussion, the protective Stella decides that they should pay rather than reveal Trevor's lies to the police. Although Monteros has ordered them to remain until the investigation is completed, Stella hires a fishing boat, under the pretense of taking a day trip to Ixtapec. Before they can leave, Monteros, who is attracted to Stella and admires her devotion to Trevor, discovers the plan and returns the money she paid to hire the boat. When Trevor goes to the house to ransom his drawings, Amigo is at a boxing match and only Maria is there. During the amicable meeting in which he gives her the money and she returns the drawings, the screech of a car outside triggers his illness and he turns aggressive. Later, as Trevor lies unconscious on the beach, Monteros goes to the Stevenson cottage to question him further about the death of the waitress. Stella, having noted Monteros' interest in her, accuses the captain of detaining them in Acapulco for unprofessional reasons. When Trevor returns, he shocks Stella by fighting Monteros, then falls unconscious. Soon after, a policeman arrives to inform Monteros that Amigo has reported finding Maria dead in his house, after he returned from his prizefight. Monteros, who is concerned for Stella, continues to question Trevor's involvement in the waitress' death and even has his young son Roberto watch out for her safety. Monteros' close friend and superior, the police chief, believes that Amigo is responsible for both deaths and that the captain's personal feelings have interfered with his handling of the case. At the chief's urging, Monteros, who is sympathetic to Trevor's war trauma, sends one of his men to tell Stella that they are free to leave Acapulco. Stella quickly packs, eager that Trevor, who is experiencing bad dreams, leave Acapulco and receive medical attention at an American hospital. Meanwhile, the police interrogate Amigo, who grieves only for Maria and not his wife. When Monteros questions him about the 6,000 pesos found in Maria's bodice, Amigo asks if the police found any of Trevor's sketches. Upon learning that the sketches are missing, Amigo confesses to blackmailing Trevor. Concerned that "love is not enough to protect" Stella, Monteros confronts her, forcing her to explain her reason for withholding the information that Trevor was at the waitress' house. Monteros tentatively accepts her explanation, but is troubled that she has not mentioned that Trevor was at Amigo's house with Maria. After the Stevensons leave for the airport, the chief allows Monteros and his men to follow them. At the airport, the noise of the planes triggers Trevor's migraines and war memories. While Stella is arranging for their flight, he wanders to the hangar and begins to relive an incident from the war, in which he fought to protect a hospital housing women and children from the enemy. Confused by a policeman's appearance, Trevor knocks him unconscious and takes his gun. Monteros, realizing that Trevor is reliving war experiences, tries to talk him out of it, but another policeman, thinking Monteros in danger, shoots Trevor point-blank. While awaiting an ambulance, Trevor dies in Stella's arms.