When Carrie and Arthur's constant fighting begins to irritate Doug, Arthur is taken to a therapist (William Hurt) to discuss why he has to yell and act up all the time. It is revealed that Arthur's problems stem from his childhood, by being horribly treated by his own father (Ben Stiller). With Arthur cured, Doug and Carrie realize that Arthur wasn't the only one with issues, leading them to take turns dealing with problems of their own.