At the beginning of the movie, it is established that 16-year old Dawn is a spoiled troublemaker and habitual liar. She doesn't care about school, detests her parents, smokes cigarettes and desperately wants a pair of cha-cha heels for Christmas (1960). One day she caught eating a submarine sandwich in class. The incompetent and misogynistic teacher, Mr. Weinberg asks for an explanation. Dawn denies eating in class. remarks that she looks she never stopped eating, seeing as she is very overweight. Mr. Weinberg forces her to write "I will not eat in class" several times, mostly in an effort to humiliate her, as he is fed up with her melodrama.
On Christmas day Dawn fails to get the cha-cha heels she wants and runs away from home and, while hitchhiking, gets picked up by Earl Peterson, (also played by Divine) Peterson drives her to a dump, where they have sex. When she later finds herself pregnant and demands money from him, he tells her off. Dawn gives birth to her daughter Taffy. For the remainder of the sixties, Dawn works as a waitress, go-go dancer, hooker, and by 1968, a petty thief.
Taffy, who is now eight years old, is a bratty child who constantly annoys her mother. Dawn punishes her by beating her with a car antenna and keeps her chained up a lot of the time.
One day at the Lipstick Beauty Salon, owned by Donald and Donna Dasher, Dawn falls in love and marries a hairdresser named Gator. Gator is the nephew of Aunt Ida, who would later become Dawn's arch enemy. Aunt Ida is devastated at the wedding and for the next five years, makes their married life a living hell for Dawn. By that time, Gator is revealed to be a pedophile, an alcoholic and a womanizer. Five years later, in 1974, she is Fed up with Gator's perversions and infidelities, and demands a divorce.
She seeks solace at the Lipstick Beauty Salon, where the Dashers ask her to be a "glamorous guinea pig" for a "beauty experiment": They want to test a theory that "crime equals beauty". They even fire Gator at Dawn's request. Aunt Ida is elated by the fact that the couple is now separated and tries to set Gator up with a gay man so that Gator doesn't have to experience the 'sick and boring life' that heterosexuals live. Gator, pissed off that he was fired, is uninterested and tells the gay man to leave. Gator decides to move from Baltimore to Detroit in order to find an automotive job. Ida is devastated by Gator's decision and plots revenge.
Donna and Donald Dasher solicit Dawn by having a spaghetti dinner. At their behest, Dawn performs several crimes including knocking her daughter unconscious during which Dawn poses for photographs when suddenly Ida bursts into Dawn's house and disfigures her face with acid and blaming Dawn for Gator leaving.
Dawn is now hideously disfigured, the Dashers convince her she's pretty and a star and discourage her from having plastic surgery. Next Dawn finds out the Dashers have kidnapped and confined Ida to an oversize bird cage. After encouragement from the Dashers, Dawn cuts off Ida's hand. Dawn, now with grotesque hair & make-up, provided by the Dashers, starts a nightclub act.
Taffy, growing weary of her mother's extreme narcissism, and years of abuse and neglect, seeks out her father, Earl Peterson. He is an unemployed, unprincipled drunk, living in the slums of Baltimore. Attempting to reconcile with her father, he solicits her for sex. After attempting to rape Taffy, she stabs him to death. Taffy, devastated by what she has done, redeems herself and becomes a Hare Krishna.
On opening night, Dawn strangles Taffy to death after discovering that she is now a Hare Krishna, while the Dashers cheer her on. Dawn performs her nightclub act, which includes jumping on a trampoline and wallowing in a playpen filled with dead fish. She then yells out, "Who wants to be famous? Who wants to die for art?" Dawn shoots into the crowd killing several people. Dawn is soon arrested by the police. At Dawn's trial, the Dashers are granted immunity in exchange for their testimony against her. Ida testifies against Dawn for kidnapping her and cutting off her hand, when actually the Dashers kidnapped Ida and told Dawn to cut off her hand (even providing her with a ax). After Dawn is found guilty and sentenced to die in the electric chair, the Dashers are seen paying Ida off. In jail awaiting execution, Dawn has an affair with another prisoner Dawn tells her being executed will make her famous, "like winning an Academy Award". as Dawn is strapped to the electric chair, she gives a speech as if she were winning an Oscar:
”I'd like to thank all the wonderful people that made this great moment in my life come true. My daughter Taffy, who died in order to further my career. My friends Chicklet and Concetta who should be here with me today. All the fans who died so fashionably and gallantly at my nightclub act. And especially all those wonderful people who were kind enough to read about me in the newspapers and watch me on the television news shows. Without all of you, my career could never have gotten this far. It was you that I burn for and it is you that I will die for! Please remember, I love every f*****g one of you!”
After the fatal electric shock, her distorted face is shown with the end credits rolling over it.