After attempting to prepare his dead wife‘s favorite dinner in her old house to celebrate the anniversary of the day they met, Monk is arrested for unlawful entry and is taken to Medford Psychiatric Institute for forty-eight hours of psychiatric observation. His roommate, overly empathic John Wurster (""I‘m a detective, too!""), informs him of an unsolved murder four years earlier, while another inmate, Manny, involves him in a quest to discover Santa Claus on the asylum roof. In addition to Dr. Lancaster‘s orders not to play detective during his stay at Medford, Monk finds his quest to solve the two ""cases"" thwarted by apparent slips of memory--a picture he doesn‘t remember drawing and another patient‘s necklace that has found its way into his pocket. After the necklace incident, Monk finds himself strait-jacketed in the ""choir room"" as the doctor‘s sinister aide goes upstairs for four cc‘s of Thorazine. Meanwhile, Sharona, who hears about the murder on a visit to Monk, examines the mur