Since the day they met, James (Liev Schreiber) and Nina (Jeanne Tripplehorn) have challenged, infuriated, enraged and adored each other completely. They are seemingly the poster couple for the perfect marriage, until, one day, Nina sees James embracing her best friend. Suddenly, her world falls apart and she is left questioning the very foundation of their marriage. Believing she has nothing to lose, Nina pretends to be another woman, striking up a relationship over the phone with her husband in an attempt to prove his infidelity. However, it is only when she is certain that her womanizing husband has fallen in love with her that Nina must face her true feelings and decide whether to walk away or give love another chance.