In the small town of Medallion, Ohio, the residents of Mrs. Murphy's boardinghouse speculate about the murder of a young college woman in Cambridge, Indiana. The woman is the second victim of a killer who has been dubbed the "Studious Strangler," due to his choice of victims. The boarders, including librarian Sally Lukens, gas man Cy Walsh and Mrs. Murphy's children, Rosie and Jerry, question fellow resident Marcus Aurelius Borne, who has just returned from a two-week vacation. Marcus, a bank teller, was near Cambridge at the time of the murder, but has no additional news for his friends. Marcus then goes to work, where bank president Harry Hammond takes a special interest in attractive Helene LaSalle, the new manager of the five-and-dime store, who is opening a new account. When he leaves for lunch, Marcus notices that he is being followed and nervously wanders about until the man reveals himself as special investigator Brad Dolan. Dolan is interested in Marcus because of his resemblance to the composite sketch of the killer, but police chief John Charters scoffs at Dolan's hunch that the mild-mannered Marcus is guilty. The boardinghouse residents are in an uproar about Dolan questioning Marcus, and in order to escape their chatter, Marcus goes for a walk with Helene, who lives next door with her aunt Jennie. Helene also despises the hypocritical residents of Medallion and promises Marcus that he can count on her friendship. As time passes, Helene and Hammond begin an affair, much to the dismay of Hammond's daughter Brooke, who wants to keep the information from her mother. Brooke, who is attracted to Marcus, asks him to meet her one night to discuss the matter, but Marcus falls asleep and misses their appointment. Another woman is strangled that night, and suspicion again falls on Marcus, who cannot easily prove that he was home asleep. Despite his preoccupation about being a suspect, Marcus agrees to help Brooke by asking Helene to end her affair with Hammond. When he talks to Helene, however, she bitterly declares that she is sick of the gossiping townsfolk and intends to fight for what she wants. Marcus goes for a long walk, and when he returns home early the next morning, he discovers that a fourth woman has been murdered. Helene supplies Marcus with a phony alibi when Dolan questions her, and Brooke, also anxious for him, drives Marcus to another town for dinner, despite her father's order that she stop seeing him. The following morning, Helene is found strangled, and although Brooke lies about what time she and Marcus returned home in order to clear him, he is again under suspicion. Marcus begins to wonder if he could have killed without knowing it, but finally realizes that he is being convicted by his former friends solely on the basis of gossip and circumstantial evidence. Embittered by their small-mindedness, Marcus castigates Hammond and his housemates for their treatment of him, then prepares to leave town. As he is packing, Marcus hears a radio report that the real killer has been captured. Despite being cleared of all suspicion, Marcus decides to leave Medallion in search of a better life.