Poison Ivy
At the opening of the film, Sylvie Cooper (Sara Gilbert) is a misanthropic student at a private high school for the privileged in Beverly Hills, California. She befriends "Ivy" (Drew Barrymore), a poor but intelligent and seductive girl attending the school on a scholarship, and Ivy quickly becomes close with Sylvie's family, to the point of moving in with them. Ivy begins to have a sexual relationship with Sylvie's father, Darryl (Tom Skerritt), as Sylvie's mother Georgie (Cheryl Ladd) becomes increasingly withdrawn from the family. Eventually, Ivy murders Georgie, making it look like a suicide.
Several weeks later, when Ivy and Sylvie are driving in Georgie's old car, Sylvie asks Ivy if she had known anything about Georgie's "suicide". To avoid the question, Ivy crashes the car, knocking Sylvie unconscious. After the crash, Ivy moves Sylvie into the driver's seat to make it look as if Sylvie had been driving.
When Sylvie wakes up in the hospital, she realizes that Ivy is dangerous and hurries home, where she finds Ivy and Darryl having sex. She runs away from them and Ivy follows her, confronting her on the balcony where Georgie had died. After an argument, the two girls fight at the edge of the balcony, and ultimately Sylvie pushes Ivy off edge, and Ivy falls to her death.