In the small city of Ogden, detective Harry Graham investigates the murder of a woman who was killed while walking near the local high school, at which music teacher Lois Conway works. The next day, Lois brings the cheerleaders she coaches to the town soda shop, where star footballer Leonard Bennett is watched carefully by every girl in the room, as well as by his overprotective father. When Lois sits down, both adoring student Sandy and Mr. Bennett immediately turn their attention to her. Bennett waxes rhapsodic about his boy, explaining that he hopes to give Leonard all the opportunities he missed when he was a child and was bed-ridden with rheumatic fever. Before leaving, Lois finds a suggestive note in her purse addressed to “Dear Teacher,” and laughs, assuming it is from Sandy. Over the next few days, however, the notes grow more obscene, and after receiving one missive asking her to rendezvous that night in the locker room, she goes, hoping to dissuade her admirer. The boy in the locker room shines a flashlight in Lois’ eyes so she cannot identify him, and then proceeds to terrorize and, finally, assault her. After she breaks out of his grasp and runs outside, crying and clutching her torn clothes, Harry spots her and brings her into the police station. There, however, Lois refuses to press charges, insisting that whoever attacked her is not a criminal but a child who needs help. Lois dropped her purse in the locker-room scuffle, but when she returns home, she finds it on her table. Realizing that the boy has stolen the notes and is in the house, she yells at to him to leave, and he dashes out the open door. When he pauses briefly outside, Lois gets a glimpse of his face and realizes he is Leonard. Leonard climbs into his bedroom window just in time for his father’s nightly visit, during which he receives a harsh lecture about the dangers of women, like his “dirty,” long-dead mother. The next day, Lois informs on Leonard to the school principal, Mr. Pendleton, but Leonard denies everything, and Pendleton, eager to protect the school’s main athletic asset, asks her for evidence. Word spreads quickly that Lois has trysted with Leonard, and her students soon become unruly, while her fellow teachers whisper in the cafeteria. One day, she pulls Leonard out of class to talk, and he warns her that the school is not big enough for both of them. Harry is waiting for her after school, and certain that Leonard is also responsible for the murder, criticizes her for empathizing with him. That night, Lois tries to talk with Bennett, who accuses her of seducing his son. Hearing that the police are involved, however, prompts Bennett to check for Leonard in his room, and, although he finds him gone, lies that the boy is asleep. Across town, Leonard aggressively pursues the soda shop waitress, who escapes when her boyfriend arrives for a date. That weekend, Harry escorts Lois to the school football game, and after overhearing that Lois requested that Leonard be disciplined, dusts Leonard’s locker for fingerprints, matching them to those on Lois’ purse. Harry then takes Lois to the school’s big dance, where, she secretly warns Leonard about the prints. Although he begins to speak openly to her, Bennett interrupts them, and later whispers to him urgently. Leonard then asks Lois to meet him in the cloak room to talk, but when she goes there, Bennett and Pendleton are hiding, and assume her appearance is proof of an affair with the teenager. Lois falls into Harry’s arms crying, and tells him to arrest Leonard. He kisses her first, and then brings Leonard in, but the boy insists that Lois invited him into her home. Bennett, recognizing Harry as Lois’ dance date, accuses him of collaborating with the “degenerate hussy.” Pendleton then puts Lois on suspension, after which Harry requests that she sit in on the next questioning session at the police station. As it begins, another man confesses to the murder, and Lois decides to drop the charges. While she, Leonard and Harry share a cab home, Bennett breaks into her house. Once home, Lois insists that Harry leave, and Bennett hides in a closet to watch her undress, then bursts out to rip out the phone and assault her. Meanwhile, Leonard, amazed that Lois would let him go after all the trouble he has caused, confesses everything to Harry, and asks to be allowed to walk home. Harry rushes back to Lois to tell her the good news, breaking in just in time to save her from Bennett, who escapes out the window. Harry chases him back to his house, where Bennett climbs up the trellis to Leonard’s bedroom window. Leonard reaches the house just as his father suffers a heart attack and falls to the ground, dead. Months later, Lois joins Harry in the soda shop after cheerleading practice, and he shows her a picture of a smiling Leonard, who has graduated and joined the military. Sandy now barely notices Lois, but a new freshman steps up eagerly to pull out her chair.