Adopted as a child, new dad Mel Colpin (Ben Stiller) decides he cannot name his son until he knows his birth parents, also determines to make a cross-country quest to locate them. Accompanied by his wife, Nancy (Patricia Arquette), and an inept yet gorgeous adoption agent, Tina (Tea Leoni), he departs on an epic roadtrip that quickly devolves to a farce of mistaken identities, wrong turns, and overzealous and love-struck ATF representatives (Josh Brolin, Richard Jenkins).