Kathryn Merte (Amy Adams) is the manipulative, cold-hearted daughter of social climber Tiffany Merte-Valmont (Mimi Rogers). Tiffany has just married again, and Kathryn is not getting along well with her new stepbrother Sebastian (Robin Dunne), who is just as skilled in the venomous art of social gamesmanship as Kathryn. Together they negotiate the tricky paths of sexual and personal power at their upscale private high school.

Kathryn and Sebastian, two wealthy, manipulative teenage step-siblings from Manhattan's upper-crust, conspire in Cruel Intentions, a wickedly entertaining tale of seduction and betrayal. The stakes are high when the duo agrees upon a deliciously diabolical wager of sexual conquest without consequences. The pawns? The naive Celcile Caldwell and the virginal Annette Hargrove. Its summer break, and Kathryn has been dumped by her beau, Court Reynolds, for the innocent Cecile. Desperate to get even, Kathryn challenges Sebastian to ruin Celcile by deflowering her and turning her into a tramp-thus humiliating Court by delivering Cecile to him as damaged goods. Sebastian has pretty much 'had' all of the girls in New York City up to this point, and he's gotten a bit bored of it all. Though this is too easy a conquest for him, he obliges. He sets his sights on a greater challenge-the new headmaster's daughter, Annette, who recently wrote an article in Seventeen Magazine about how she intends to stay pure until she marries her boyfriend. Sebastian bets Kathryn that he can seduce the chaste and pristine Annette before school begins in the fall. Kathryn thinks this feat impossible and quickly agrees to the wager. The stakes: if Sebastian succeeds, Kathryn must give him a night of unbridled pleasure, something's he's wanted since their parents got married. If he fails, he must forfeit his priceless 1956 Jaguar to Kathryn and suffer the shame of defeat.

Tom Welles (Nicolas Cage) is a surveillance expert on the rise. He's living the American dream with a wife, Amy (Catherine Keener), infant daughter, and a house in the suburbs of Harrisburg, Pennsylvania. After the completion of an assignment for a U.S. Senator, Welles is summoned to the house of a recently deceased captain of industry. His widow, in settling his estate, has discovered an 8MM film in her late husband's private safe. The silent short depicts the apparent murder of a young woman by a large, masked figure, what is known as a "snuff" film. Greatly disturbed by the film's contents, the widow hires Welles to find the identity of the woman and determine if she is still alive. Welles finds the girl's identity and follows her trail from the time she ran away from home to Hollywood. Once there, Welles meets adult bookstore clerk Max California (Joaquin Phoenix) to act as Virgil to Welles' Dante. As the two begin their descent into the world of underground pornography, the detective grows more and more distant from his family, as if he cannot shake the taint of the world in which he now walks. Tom and Max eventually meet pornographers Dino Velvet (Peter Stormare) and Eddie Poole (James Gandolfini). By this time the detective finds he can no longer walk out of the inferno.