Stacy (Brittany Murphy) is a young woman working as an associate producer on a daytime talk show hosted by Kippie Kann (Kathy Bates). Stacy is in a happy relationship with Derek (Ron Livingston), a young executive who works at a Jingle Writing Company.
As Stacy's relationship with Derek progresses, she becomes increasingly curious about his past relationships. She turns to her colleague Barb (Holly Hunter) for help and the two of them come up with a plan to create a "little black book" of Derek's ex-girlfriends.
With the help of a private investigator, Stacy and Barb track down and interview Derek's ex-girlfriends, posing as producers for Kippie Kann's show. As Stacy delves deeper into Derek's past, she discovers that he may not be the person she thought he was and begins to question the future of their relationship.
Meanwhile, Stacy befriends one of Derek's ex-girlfriends, a successful model named Joyce (Julianne Nicholson), who reveals even more about Derek's past than Stacy bargained for. As Stacy struggles to reconcile what she learns with her feelings for Derek, her plans to produce the perfect segment for Kippie Kann's show begin to unravel.
In the end, Stacy must decide whether she can trust Derek and move forward with their relationship or if she should listen to her gut and cut ties with him for good.