New York lawyer Carly Whitten (Cameron Diaz) lives by strict rules when it comes to romantic relationships, but when she falls for suave, handsome Mark King (Nikolaj Coster-Waldau), she begins an affair with him. A surprise visit to Mark's home reveals that he is married to devoted housewife Kate (Leslie Mann). Carly and Kate direct their hurt and anger toward Mark, and when they discover yet a third woman (Kate Upton) caught in his web of lies, the three join forces for revenge.