After years of prostituting herself along the highways of Florida, Aileen “Lee” Wuornos sits in the rain by the side of the freeway and contemplates ending her life with a gun she is holding. Deciding to spend her last five dollars on getting drunk, Aileen walks into a gay bar and orders a beer. When Selby Wall, a young lesbian with her arm in a cast, sits down next to Lee and offers to buy her a drink, Lee, horrified that Selby might think she is a lesbian, lashes out at the girl. However, after Selby assures Lee that she is lonely and just wants to talk to someone, the two share drinks until closing time when Lee’s belligerent attitude prompts the bartender to throw them out. Selby then invites Lee home to spend the night. There Selby caresses the love-starved Lee’s face, but the next morning, their tranquility is shattered when Donna Tentler, a friend of the Walls with whom Selby is staying, bursts into the room and demands to know what is going on. After Lee makes arrangements to meet Selby at a roller rink later that night and hurriedly leaves, Donna warns Selby never to bring “people like that” home again. Lee proceeds to a warehouse in which her possessions are stored and there meets her friend Tom, a kindly father figure who gives her a sandwich and a beer. Later, Lee prepares for her date with Selby by styling her hair in the bathroom of a gas station. At the roller rink, Selby tells Lee that she thinks it is “wild” that people actually pay to be with her and explains that her father sent her to Florida after she was accused of trying to kiss a girl back home in Ohio. Lee pulls the reluctant Selby onto the rink and the two glide along, staring romantically into each other’s eyes. Later, their passionate kissing in the alley outside the rink is observed by Trevor, Donna’s son. The next day, as Lee solicits along the highway, Donna informs Selby that Trevor reported seeing her in the alley. Donna has conveyed the information to Selby’s father, who wants his daughter to return to Ohio immediately. After having sex with one john, Lee is picked up by Vincent Corey, who drives her into an empty field and demands that she perform oral sex on him in addition to the previously agreed-upon fornication. Impatient to keep her date with Selby, Lee refuses to perform both acts, after which Corey bashes her in the head, ties her hands to the car door and brutally rapes her with a pipe. When he pours alcohol on her wounds, Lee, fearing that he is about to kill her, flies into a frenzy, and wrenching her hands free, pulls her gun from her jacket and shoots him several times, then, howling in fury, pistol-whips him. After covering up the body, Lee wipes the blood from her face and drives off in Corey’s car to see Selby. Lee’s tapping on Selby’s window awakens Donna, who summons her husband Charles to chase off the vagrant. Although Selby is angry at Lee for not keeping their date, she runs outside to warn her to leave and informs her that she has agreed to return home to Ohio. Promising to put Selby on a bus bound for home if she is unhappy, Lee hands her the cash she has made from soliciting and begs her to stay with her for one week. Selby accepts Lee’s offer, and the two drive off in Corey’s car. After checking into a roadside motel, Lee takes Selby to her hangout at The Last Resort, a biker bar in Port Orange, Florida. Later, as Lee drives Corey’s car into the woods and wipes it clean of fingerprints, Selby returns to Donna’s to collect her belongings. Donna then calls Selby’s father, who berates the girl and demands that she come home. Thrusting the phone at Donna, Selby leaves and returns to the motel to tell Lee she has decided to stay with her. Overwhelmed with happiness, Lee promises to take care of Selby, but when Lee vows to “quit hooking,” Selby worries about how she will support them. Lee naïvely replies that she will get a career-level job like veterinarian or “business person.” However, when Lee tells one of her potential employers that she has no experience and no work history, the man laughs, prompting Lee to swear at him. When Lee recounts her humiliating rejection to Selby and admits that she has run out of money, Selby whines that she is hungry and worries over how Lee will provide for her. After failing to find any work at the employment office, Lee is about to throw out the employment section of the newspaper when she spots a story stating that Corey’s body has been found. Upon returning to the motel, Lee is confronted by Selby, who is upset that Lee has curtailed their income by refusing to solicit men. Lee then confesses that she killed her last john after he raped and beat her. When Lee states that she was afraid the man was going to kill her, Selby apologizes and Lee shows her the murder story in the paper, then admits that she stopped soliciting because she was fearful of getting caught. Conceding that she has been hooking since she was thirteen years old, Lee resigns herself to a life of prostitution and returns to picking up johns along the road. One night, a john drives Lee into a deserted field, and when he asks her to call him “daddy,” she shoots him. As Lee drives off in the dead man's car, she muses about a Ferris wheel from her childhood dubbed “the monster.” The wheel magically lit up the night sky, but when she rode on it, she became nauseous and vomited. Upon returning to the hotel, Lee hands Selby a fistful of cash, then muses that in her life, the “harmless stuff always hurts the most…[but] things so horrible don’t bother her.” After a night of passionate love making, Lee rents Selby an apartment and carries her over the threshold. Later, Lee is picked up by a nervous, stuttering john who admits that it is his “first time.” When the man puts his wallet on the dashboard of his car and tells her to take what she wants, Lee masturbates him and he thanks her. Afterward, Lee continues soliciting, and upon returning home, cuts out a newspaper story about another murder and stuffs it into a box. The next morning, Selby, disgruntled about being left home alone while Lee is out working, drives off in one of the dead men’s cars that Lee has driven home. Selby goes to a lesbian bar where she meets several women who tell her about a place called “Fun World.” When Selby comes home, Lee chastises her for taking the car, prompting Selby to accuse Lee of “scaring off people,” and insists that she take her to Fun World. There Selby sees the women from the bar and goes off with them. Later, Selby asks Lee to join her on the Ferris wheel. Remembering her sickening childhood experience, Lee smiles wanly and joins Selby. As Selby drives them home, Lee tells her that she turned to prostitution to support her younger brother and sister, who called her a "whore" when they found out. Mesmerized by Lee’s story, Selby misses the turnoff, and when she makes a sharp turn, the car careens out of control and smashes into someone's front yard. When the owners of the house run out, Lee speeds off, then abandons the car. After Selby complains that she wants to drive in the car rather than walk, Lee informs her that the vehicle belongs to a dead man. As they hurriedly pack their clothes to flee, Lee shows Selby the box stuffed with clippings about the murders. Selby protests that Lee cannot go around killing people, to which Lee responds that she "is good with the Lord and people kill each other every day.” To steal a car for their getaway, Lee picks up another john, but when Lee begins to talk about her rape and expresses her rage toward men, the older john becomes nervous. Pulling out her gun, Lee shoots him and upon examining his wallet, discovers that he was a retired policeman. At The Last Resort, Lee tells Tom goodbye, wailing that she had no control over what she did and never had a choice. As the couple who saw the crash provides the police sketch artists with a description of the women, Lee, urged by Selby to secure another car, walks the highway looking for a john. A kindly, elderly man stops and offers Lee a room and some clothes. Unnerved, Lee tries to get out of the car, but when he sees the gun slip out of her pocket, she forces the man to drive into the woods and shoots him, even though she feels profound anguish for her actions. When Lee returns home, Selby tells her about seeing their sketches on a television news broadcast. Realizing that they are in danger, Lee takes Selby to the bus station where Lee breaks down and begs her to come back one day. After giving Selby the last of her money and putting her on a bus headed for Ohio, a depressed Lee leans dejectedly over a bridge and throws the gun into the water below. At The Last Resort, Lee is met by Tom, who admonishes her to leave the bar. When Lee insists on waiting for Selby’s call, an undercover policeman posing as a biker offers to give her change for the pay phone. While following the man to his car to get the change, Lee is apprehended by the police. Arrested on an old warrant, Lee is taken to prison where Selby phones her as the police record the conversation. Although Lee tries to discuss their relationship, Selby is only interested in manipulating her into taking sole responsibility for the murders. Although Lee realizes that Selby is setting her up, she vows her love for Selby then states “it was me and only me,” as the police record their conversation. Lee’s confession is played in court, where Selby takes the stand and testifies against her former lover. After the judge sentences Lee to death, she tells him to "rot in hell [for] sending a raped woman to death." As Lee recalls all the empty platitudes she has heard in her lifetime, the police lead her away.