Thirty-four-year-old psychologist Richard Clayton's (Ron Livingston) parents reveal to him that he was adopted. He then sets out to find out who his biological parents are, but disaster ensues when it turns out that his parents, Frank (Danny DeVito) and Agnes Menure (Kathy Bates), are crude, lower class carnies. They follow him home and cause chaos to his normal life. There are frequent references to the movie ''Mother, Jugs & Speed'' used by the characters in the film.