Doctor Leo Marvin, an egotistical psychotherapist in New York City, is looking forward to his forthcoming appearance on a "Good Morning America" telecast, during which he plans to brag about "Baby Steps," his new book about emotional disorder theories in which he details his philosophy of treating patients and their phobias. Meanwhile, Bob Wiley is a recluse who is so afraid to leave his own apartment that he has to talk himself out the door. When Bob is pawned off on Leo by a psychotherapist colleague, Bob becomes attached to Leo. Leo finds Bob extremely annoying. When Leo accompanies his wife Fay, his daughter Anna, and his son Siggy to a peaceful New Hampshire lakeside cottage for a month-long vacation, Leo thinks he's been freed from Bob. Leo expects to mesmerize his family with his prowess as a brilliant husband and remarkable father who knows all there is to know about instructing his wife and raising his kids. But Bob isn't going to let Leo enjoy a quiet summer by the lake.