In the opening scene, we are introduced to four high school girls whom are blessed with beauty and charisma. They are known as the "Flawless Four" who are the most popular girls in Reagan High School in southern California. The clique consists of Courtney Shayne (Rose McGowan) known as Satan-in-heels; Marcie Fox (Julie Benz) known as 'Foxy'; Julie Freeman (Rebecca Gayheart); and Elizabeth Purr (Charlotte Ayanna), known as the "Princess Di of Reagan High." Of the four, Elizabeth Purr was the only one who was genuinely kind-hearted and loved by the entire school. Julie was "doomed to be popular because of 'that face' and because she was best friends with Elizabeth Purr". Cold-blooded queen bee Courtney and her airheaded friend, Marcie, demand respect through terror.However, Courtney, Marcie and Julie play a mindless prank on Liz the morning of her seventeenth birthday, by performing a fake kidnapping: They surprise Liz in bed, bind her with ropes (with Courtney ramming a jawbreaker candyball into her mouth to gag her) and cover it with duct tape. The girls trap Liz, dressed only in a shirt and panties, in the trunk of a car, as she struggles and squeals through her gag, and drive off. They plan to take the bound, gagged, and helpless girl to a restaurant and "stuff her face with pancakes". However, upon opening the trunk, they are greeted with the grisly sight of Liz dead, having choked to death by aspirating the jawbreaker into her larynx.Horrified, Julie wants to go to the police but Courtney forbids her. Instead, Courtney calls the school pretending to be Liz's mother and tells them Liz is ill and cannot attend school. To keep up appearances, Courtney, Marcie and Julie then go to school as though nothing had happened. When the principal sends school outcast Fern Mayo (Judy Greer) to deliver Liz's homework at the end of the day, she stumbles upon the three girls and Liz's mangled and decomposing body. Out of jealousy, Courtney fabricates a story that Liz died at the hands of a rapist, and plots to tarnish Liz's good reputation by spreading false rumors that she was actually a rebellious, promiscuous girl, and not the perfect angel she made herself out to be.Fern, who had admired Liz to the point of hero worship, is appalled and attempts to flee the house, but the girls easily catch her. To buy Fern's silence, Courtney accepts Fern into the clique, telling her to take Liz's place. Courtney and Marcie then give her a makeover, transforming her from plain and awkward to elegant and beautiful. Later in the school cafeteria, Courtney introduces Fern as the beautiful exchange student "Vylette." Julie, overwhelmed by guilt at her part in Liz's death, distances herself from the clique, only to be shunned and tormented by her former friends and becomes a new target for abuse throughout the school. Her only real friend during this time is her drama student boyfriend, Zack.Meanwhile, a police detective, Vera Cruz (Pam Grier) begins investigating Liz's death after her body was discovered by her parents who arrived home from a long vacation. With some cooperation from the wary principal Ms. Sherwood (Carol Kane), Detective Cruz interogates all of Liz's friends (Courtney, Marcie, and Julie included). All of them deny knowing anything about Liz's death. Fern/Vylette however comes across as suspicious due to her demeanor. But without any evidence, Cruz allows 'Vylette' to remain free.As Vylette's popularity soars, Julie watches in mute horror as Courtney spins a relentless web of lies, trickery and manipulation to cover up the murder and maintain her popularity at the school.A few days later, Julie learns from Detective Cruz (to her disgust) that after they'd returned Liz's corpse to her house, Courtney went out and seduced a stranger (Marilyn Manson) at a sleazy bar and had sex with him in Liz's bed, making it seem as though he had raped Liz.Meanwhile, Vylette becomes intoxicated with her newfound popularity, which has eclipsed Courtney's own. Realizing she has created a monster, Courtney threatens to reveal the truth about Vylette if she doesn't stop showing off, but Vylette vows she will reveal the whole truth about Liz's death if Courtney attempts to expose her.The next day, an infuriated Courtney and Marcie post enlarged yearbook photos of Fern Mayo all over the school with the message "Who is Vylette?" written on them, revealing Vylette's true identity. Fern is thoroughly humiliated by the entire school and once again reduced to an outcast. Feeling no remorse for the lives she has destroyed, Courtney casually attends the senior prom with her boyfriend, jock Dane Sanders (Ethan Erickson).Julie takes pity on Fern and forgives her for falling under Courtney's influence. Later that night as she sulks in her room, going through a bag of Liz's belongings that were given to her, Julie finds the recording card she was fiddling with when Courtney was faking Liz's death and discovers it has incidentally recorded Courtney's admission to the murder. Struck with an idea, Julie, Fern and Zack all hurry to the prom. Upon seeing them, Courtney, Marcie and a few of their lackeys call Julie and Fern names and try to embarrass them, but it backfires when the girls completely ignore their taunts and go on with their plan.Later on, as Dane and Courtney are announced as Prom King and Queen, Zack sneaks backstage and broadcasts the card message, "I killed Liz! I killed the teen dream! Deal with it!", over the sound system while Courtney is making her acceptance speech. Dane (seized with shock and disgust over the revelation) quickly abandons Courtney. Marcie also runs and hides to distance herself from Courtney. Horrified that her scheme has become unraveled, she races for the exit as the rest of the students pelt her with corsages and call her a murderer. Awaiting Courtney at the very end of the mob is Julie, who gleefully snaps a picture of her former friend's anguished face to immortalize the occasion.