Dawn Davenport (Divine) is a rebellious bad-girl teenager who smokes cigarettes, uses hairspray, and doesn't care about school. Dawn and her two best friends, Chicklette (Susan Walsh) and Concetta (Cookie Mueller), discuss the upcoming Christmas holiday. All three of them intend on using Christmas simply for financial gain, but Dawn has something particular in mind; she has requested "cha cha heels", and she assures her two friends that there will be trouble if her parents let her down.
Christmas morning, Dawn's very square parents wake her up to open presents, and Dawn makes a beeline for a certain package the size of a shoebox; it does contain shoes, but not cha-cha heels. "Nice girls don't wear cha-cha heels!" exclaims Dawn's father, but Dawn is furious. She stomps on the rest of the Christmas presents, hurls her mother into the Christmas tree, and curses her parents, running away from home.
Outside in her nightgown, coat and slippers on Christmas morning, she is picked up by a sleazy-looking man named Earl Peterson (also played by Divine). Earl takes her to a dump and has sex with her on a dirty mattress, and Dawn steals his wallet. Nine months later, Dawn is living in a cheap hotel and very pregnant. She phones Earl at work and demands money, but he hangs up on her. Dawn stumbles back into the hotel and immediately gives birth to a baby girl she names Taffy, cutting the umbilical cord with her own teeth.
Years later, Taffy is an obnoxious preteen girl, and Dawn is working in a number of jobs, including a waitress, a stripper, and a prostitute. She also is a petty thief, working together with Chicklette and Concetta. After Taffy erupts with some particularly annoying behavior, the frustrated Dawn gets Chicklette and Concetta to help chain the child to her bed in the attic. Dawn is despondent about the pressures of being a mother, and Chicklette and Concetta encourage her to pamper herself by getting her hair done at The Lipstick Beauty Salon, where patrons must audition for an appointment.
Dawn is immediately favored by the snobbish owners of The Lipstick, Donald and Donna Dasher (David Lochary and Mary Vivian Pearce). She also gets her hair done by Gator Nelson (Michael Potter), who proposes marriage the same day. Gator just happens to be Dawn's next-door neighbor, where he lives with his Aunt Ida (Edith Massey), an obese, elderly woman who dresses outrageously and encourages her nephew to be gay. Aunt Ida is heartbroken when Dawn and Gator get married, and she clashes with Dawn repeatedly thereafter.
Dawn and Gator are married for five years before things start to fall apart. Gator cheats on her with various women, while Ida harasses her by doing things like dumping garbage in her back yard. Taffy grows into a strange teenager who likes to play "car accident", where she re-enacts fatal car crashes using props. One day, after a bad fight with Gator (he places a carrot in Dawn's mouth during sexual climax), Dawn goes to get her hair done and is called into the private quarters of the Dashers, who inform her that they want her to be a model for them. The Dashers are obsessed with crime and feel that it is connected to beauty, and they ask that Dawn be their "crime model". In return, she gets special treatment and they immediately honor her request to fire Gator.
Gator becomes enraged and decides to leave Baltimore for Detroit, so that he can become part of the auto industry. Aunt Ida, who is still trying to fix Gator up with other men, becomes insane with sadness. Before Gator leaves, he punches Dawn in the face and gives her a black eye. The Dashers join her at her home for dinner that evening and are thrilled by her black eye, photographing it. Taffy embarasses Dawn by starting an argument, and Dawn smashes a chair over her back, rendering her unconscious. The Dashers are thrilled, photographing the fight, but they are even more excited when Aunt Ida forces her way into the house and hurls acid in Dawn's face, scarring her for life.
After Dawn recovers from her wounds, her face is horribly mutilated, but the Dashers convince her that her wounds are 'beauty marks', and she refuses plastic surgery. They also redecorate her home and buy her new clothes. Dawn's final treat is Ida herself, kidnapped and imprisoned in a bird cage for Dawn's amusement.
Taffy enrages Dawn by insisting that Dawn tell her the whereabouts of her father, Earl, but when Taffy finds him, he makes drunken sexual advances towards her. As a result, Taffy stabs him to death and runs from the scene.
The Dashers escalate their experiment with Dawn, injecting her with liquid eyeliner and telling her it is like drugs. Dawn is so influenced by them that she no longer knows what is real and what isn't. They design a stage show for her, and on opening night she is visited backstage by Taffy, who has converted to a hare krishna. Dawn strangles her to death in front of the Dashers and her friends, who cheer her on. On stage, Dawn fires a gun into the crowd, killing an audience member. A riot breaks out, with several more audience members killed in the melee. The Dashers are arrested, but Dawn escapse and hides out in the woods. She isn't a fugitive for long; she is found and brought back to Baltimore for trial.
Dawn feels no remorse for her crime, considering the trial the highest reward for her 'career', but she is outraged when the Dashers turn tail and try to deny their involvement in everything. For their testimony they are granted immunity, and Dawn gets the death sentence. Her stint in jail leads her to believe she is a superstar, and her criminal celebrity will endure after she is dead. As they strap Dawn into the electric chair, she launches into a speech where she thanks everybody for this crowning moment, and they throw the switch, killing her.