Sabra Tanner (Susan Cabot) is a rich sorority girl at a boarding school for girls. She shares a room with Rita Joyce (Barboura Morris), the students' association leader. She behaves as though the place belonged to her and she especially enjoys terrorizing young freshgirl Ellie Marshall (Barbara Crane), although that is not allowed. Ellie is meek, and thinks that if Sabra opposes her nobody in the school will want to talk to her ever again.Sabra is so used to getting what she wants that she is even rude to her mother (Fay Baker) while they are having lunch together at a nice restaurant. The problem is that Sabra won't get any of her late father's money if she doesn't finish her university studies, as stated in his will. Meanwhile, her mother has control over her and her father's inheritance.Sabra comes to know her roommate's secrets by opening a box she keeps always locked. She also uses the knowledge of Tina's (June Kenney) pregnancy against Mort (Dick Miller). Mort is the owner and main waiter of the only local bar/beach pub. Sabra plots to get some money from him by blackmailing him, but she won't succeed: Mort has recorded the conversation in which Tina admits that he's not the father of her child but that she will say so in order to get some money from him.Sabra keeps on plotting and scheming, and it comes a moment when she tells herself to stop creating havoc on the school. Mrs Fessenden (Jeane Wood) is the strict headmaster of the school but she doesn't suspect Sabra.Sabra tries to hold a conversation with her mother, in which she admits that she hurts people for the sake of it, and that sometimes she makes too much damage to people who won't be able to deal with it. Sabra is talking while her mother is sunbathing. Her mother thinks it's just a scheme of hers to make her feel soft with a view to obtaining some more money from her. Her mother dismisses her daughter away nonchalantly, laughing about her and not paying any attention to her problems.So Sabra feels lonely at school. Soon she has to go to a beach excursion with her schoolmates and all her plots and schemes are revealed when Tina almost commits suicide. Rita is the leader of those who oppose her. Sabra becomes lonely and falls into the water as now everybody knows what she's done.
A poor-little-rich-girl feels alienated by her mother and enacts a string of torment on her fellow pupils at a girls' boarding school, increasingly aggravating them until she goes too far.