A confused Monk is found trespassing in the home of his late wife, Trudy, and is sent to the Medford Psychiatric Institute for bservation. Monk meets the hospital's brilliant director, Dr. Morris Lancaster, as well as fellow patients John Wurster (Kevin Nealon) - an overly empathic, Zelig-type ("I'm a detective too!") -and Manny, a man in his thirties who still believes in Santa Claus. Wurster tells Monk about a murder that took place at Medford four years earlier and Monk soon finds himself on the case.