Dr. Richard Clayton (Ron Livingston) has it all: A loving fiancée, Ellen (Neve Campbell), two wonderful, supportive parents, a successful career as a psychiatrist and a self-help book on anger management climbing the best seller list. Everything in his life is right on course... until his jealous brother tells Richard he was adopted. Enter his birth parents Frank and Agnes Manure (Danny DeVito and Kathy Bates): A couple of crude, unrefined and offensive Carnies. Frank and Agnes proceed to make Richard's life miserable, from nearly destroying his relationship with his adoptive parents and close friends, to sabotaging his career and nearly ruining his approaching marriage. Although Richard's life appears to be in shambles, he learns that he may have something to learn form Agnes and Frank Manure after all.