In New York City, a wealthy teenager Sebastian Valmont regularly manipulates and seduces women, always seeking a real challenge to test the limits of his charm. He sets his sights on Annette Hargrove, Kate Levering the daughter of his new school headmaster, who is steadfastly opposed to sex before marriage. Sebastian teams up with his equally cunning stepsister, the intelligent and popular Kathryn Merteuil, Sarah Michelle Gellar, and the two hatch a bold bet: if Sebastian fails to seduce Annette, Kathryn will get his vintage Jaguar XK140; if he wins, Kathryn will finally have sex with him. Kathryn also hatches a plan to recruit Sebastian into a retaliation scheme against her ex-boyfriend Court Reynolds, who left her for Cecile Caldwell.
Sebastian’s early attempts to win Annette’s heart are clumsy, partly because she’s wary of his reputation. He begins to suspect Annette’s close friend Greg, a closeted young man, and uses blackmail to pressure Greg into persuading Annette of his “good nature.” He also learns that Cecile’s mother warned Annette and decides to corrupt Cecile as part of the larger payback. Kathryn quickly spots a different dynamic at play: she notices romantic tension between Cecile and their music teacher Ronald Clifford and leaks this to Cecile’s mother, which results in Ronald’s dismissal. To fuel Cecile’s vulnerability, Sebastian and Kathryn coax Ronald into writing a love letter that Sebastian uses to lure Cecile to his bedroom, where he pressures her into receiving oral sex. The next day, Kathryn advises Cecile to sleep with Sebastian and be as promiscuous as possible to satisfy Ronald.
As Sebastian spends more time with Annette, he begins to develop genuine feelings for her—drawn to her honesty and the way she makes him laugh. He kisses Annette, but she resists at first, fearing she cannot restrain herself around him. He accuses her of hypocrisy for rejecting true love, and she finally relents, beginning to undress, yet Sebastian, torn by his own confusion, declines to have sex. Annette leaves, but Sebastian finds her again, confesses his feelings, and they ultimately share a night of intimacy.
A jealous Kathryn tries to reclaim control, failing to win back Sebastian’s affection as his love for Annette grows stronger. She presses him to accept that his nature cannot be changed, and she warns him that telling Annette the truth about the bet could ruin both of them. He decides to reveal nothing at first, later telling Annette that he only sought sex, and that his feelings were not real. He breaks up with her, hoping to end the hurt, while Kathryn dismisses his claims and reveals that he was the real target all along, using him to fuel her own amusement.
Sebastian longs to tell Annette the truth and seeks a second chance, but she refuses to see him. He leaves his journal with her, a detailed record of Kathryn’s manipulations, the bet, and his true feelings for Annette. Enraged, Kathryn calls Ronald and accuses Sebastian of hurting her and sleeping with Cecile. Ronald confronts Sebastian in a violent outburst that spills into the street. Annette tries to intervene but is thrust into traffic, and Sebastian is struck by an oncoming taxi, sacrificing himself to push her to safety. In the aftermath, they confess their love for each other, but Sebastian dies from his injuries.
At Sebastian’s funeral, Kathryn’s coldly delivered eulogy falls on deaf ears as people depart in search of honesty elsewhere. Cecile disperses copies of Sebastian’s journal, titled Cruel Intentions, exposing Kathryn’s manipulations, promiscuity, and drug use, shattering her carefully curated “good girl” image. In the final, bittersweet moment, Annette drives down a highway in Sebastian’s car, wearing his sunglasses with his journal by her side, cherishing the memories of their time together.
