The Allgoods are a close family experiencing life's typical ups and downs: 18-year old daughter Joni (Wasikowska) is heading off to Stanford University and starting to distance herself from her parents; 14-year-old Laser is hanging out with a deadbeat friend who constantly leads him into trouble. The only difference is that this family has two mums. Jules (Moore) and Nic (Bening) have been together for years, deeply in love, and had both children through artificial insemination.

This loving but strained home life is thrown into comic disarray when the kids track down their biological donor-Dad, Paul (Ruffalo), and invite him home for dinner.