When single executive Kate Holbrook (Tina Fey) decides the time is right to finally have a baby, she hires a working-class woman (Amy Poehler) from South Philadelphia to act as her surrogate mother. However, Kate's careful planning goes out the window when the woman shows up on her doorstep needing a place to live. A comic battle of wills breaks out between the pair as they prepare for the blessed event and try not to kill one another in the process.