Sylvie Cooper, a misfit high school student, watches a free-spirited, sexy teenager on a rope swing in the park, and sketches her portrait. Later, the girls meet outside the high school principal’s office. Sylvie admires the girl’s temporary tattoo of a cross covered with ivy, and learns she is there on a scholarship. However, her low grades in biology are a problem. Sylvie admits to calling in a bomb scare to a television station after disagreeing with an editorial by her father, Darryl, the general manager. Darryl arrives at the school, furious, and Sylvie apologizes. When the other girl asks for a lift home, Darryl refuses. However, Sylvie convinces him to give a ride to her new best friend, “Ivy.” Sylvie asks Ivy for her real name, but she insists on using her new alias. Later, at the park, Ivy admires Sylvie’s jewel necklace, and she explains it was a gift from Darryl, who adopted her after marrying her mother. Ivy declares she is lucky to receive such gifts, and claims her own father is abusive. Sylvie shares that she tried to commit suicide by slitting her wrist and shows Ivy the scar. They walk home together and Ivy is impressed by Sylvie’s expansive home. Inside, they are greeted by Sylvie’s dog, Fred, who does not like anyone but her, and Sylvie asks Ivy to be quiet because her mother, Georgie, is ill. However, Georgie comes downstairs, and shows disdain for Ivy. As Sylvie helps her mother back to bed, Georgie states she does not want her daughter hanging out with such a low class person. Sylvie attempts to adjust her mother’s oxygen mask, which is not working, and Ivy arrives and fixes the inhaler. The girl reveals that her mother died of a cocaine overdose, and she now lives with an aunt who is paid to be her caretaker. Ivy wins over Georgie, ingratiates herself to the family, and soon becomes a fixture in their home. Georgie lends Ivy clothing, and Sylvie takes her shopping. Later, as the girls sleep side-by-side, Sylvie admits that Darryl is her real father, and that she never tried to kill herself, but was hurt in an accident. At breakfast, Darryl is upset with Georgie’s dependence on medication and they argue. Sylvie tries to intervene, however, Georgie ignores her daughter and asks Ivy to help her back to her bedroom. When Ivy joins Sylvie at the bus stop, she suggests they skip school. The girls go to a tattoo parlor where Ivy gets a permanent rendition of the cross encircled with ivy, and convinces Sylvie to also get a tattoo. The girls return home and discover Georgie standing on her balcony ledge. Believing she might be attempting suicide, they pull her back inside. Sylvie tries to talk with her mother, but Georgie is too tired. That night, Darryl removes his toupee, gets a midnight snack, and encounters Ivy. She flirts with him, claiming she finds him attractive without the hair piece. Later, Darryl is concerned about keeping his job, and plans to have a party to impress his colleagues. Sylvie promises to help her father, but Ivy answers Sylvie’s phone and commits her to chaperoning a “Head Start” outing on the day of the party. She “forgets” to mention it to Sylvie, who is surprised when the van arrives just before the party. Ivy insists she feels like a fool for the “mix-up,” and offers to help with the party. She borrows one of Georgie’s sexy gowns and serves champagne to the guests. Although Darryl is a recovering alcoholic, he claims it is okay to drink champagne because he has resolved his addiction. After the party, Ivy dances seductively and Darryl joins her. Georgie interrupts them and rushes back upstairs, upset. When Darryl follows her, Georgie demands several pills, which he gives to her. Ivy brings champagne, claiming the dress reminded Darryl of his ill wife. She insists that she found him crying and embraced him as a friendly gesture. Georgie accepts the explanation, and after she falls asleep, Ivy moves seductively toward Darryl and they fondle each other next to Georgie’s unconscious body. Later, Sylvie returns home, and is jealous to find her dog, Fred, sleeping next to Ivy. The next morning, Darryl drinks vodka, but hides the glass from his daughter. Sylvie is outraged to find Ivy and Fred in her mother’s convertible, unaware that Ivy lures the animal with treats. Sylvie pretends to leave for school, but retreats to the park instead. After school, Darryl picks up Ivy, and they make love. Sometime later, Ivy apologizes to Sylvie about the dog, and the girls reconcile. As Georgie listens to a recording of music that Sylvie wrote for her, she wanders to the balcony. Ivy joins her and pushes Georgie over the ledge to her death. Darryl and Sylvie believe Georgie committed suicide. Days later, Darryl is fired from his job. Ivy gets Georgie’s urn and convinces Sylvie to go for a drive in the convertible to honor her mother. Ivy races recklessly down the winding mountain road, humming a tune, and Sylvie realizes it is the song she wrote for Georgie. Now aware that Ivy was present at her mother’s death, Sylvie demands to know what Georgie said before killing herself, and Ivy becomes irate. She asks if Sylvie is accusing her of killing Georgie, and crashes the car into a tree. Although Ivy hits the steering wheel, she remains conscious, but Sylvie smashes into the windshield and is rendered unconscious. Ivy moves Sylvie to the driver’s seat and smears her blood on the steering wheel. Sylvie awakens in the hospital and tries to convince her father that Ivy is responsible for the accident and Georgie’s death, but he assumes she is incoherent due to head trauma. Later, Sylvie sneaks out of the hospital and returns home, and sees Darryl making love to Ivy. As her father chases Sylvie outside, he trips on the stairs. Ivy promises to find Sylvie, but Darryl sees her bruises from the steering wheel and realizes that she lied about the automobile accident. As he drives off to find his daughter, Ivy goes to Georgie’s room. Sylvie watches from outside as Ivy stands on the balcony ledge. She goes to her mother’s room to confront Ivy. Due to her head injury, Sylvie hallucinates a vision of her mother. She declares her love, and “Georgie” kisses her. However, Sylvie quickly realizes Ivy is kissing her, and pushes the girl away. As Ivy falls off the ledge, she grabs Sylvie’s necklace. She threatens to take Sylvie with her, but the necklace snaps and Ivy falls to her death.