An advice columnist, Andie Anderson (Kate Hudson), tries pushing the boundaries of what she can write about in her new piece about how to get a man to leave you in 10 days. Her editor, Lana (Bebe Neuwirth), loves it, and Andie goes off to find a man she can use for the experiment. Enter executive Ben Berry (Matthew McConaughey), who is so confident in his romantic prowess that he thinks he can make any woman fall in love with him in 10 days. When Andie and Ben meet, their plans backfire.
Kathryn Merteuil and Sebastian Valmont are seductive, manipulative step-siblings who get what they want when they want it. Kathryn makes a bet with Sebastian: Sebastian must bed Annette, daughter of the headmaster at their school, before the end of summer break. Annette has stated that she would wait until love and marriage to sleep with a man. If Kathryn wins, she gets Sebastian's vintage 1959 Jaguar Roadster. If Sebastian wins, he gets Kathryn, the only girl he knows he'll never have. Also in play is Cecile, a naïve girl whose mother had enlisted Kathryn to help her fit in at her new school. However, Kathryn (with Sebastian's help) plans to ruin Cecile's reputation as revenge on Kat's ex-boyfriend, who left her for Cecile.