Kate Holbrook (Tina Fey), a successful single businesswoman from Philadelphia, has put her career before her personal life. At the age of 37, she has finally decided to have a child on her own, but her plans change when she discovers she has only the slimmest chance of becoming pregnant. Also denied adoption, Kate hires an immature, obnoxious South Philly girl, Angie Ostrowiski (Amy Poehler), to become her surrogate mom.