On Halloween, an armored car driver is shot several times with his own gun. Monk is called from the crime scene by Ambrose, who says that their father is coming to visit, but not before Captain Stottlemeyer shoos away a pigeon and Monk finds a clove cigarette on the ground. While the captain interviews a witness and discovers that the hugger was not after money, the Monk brothers wait for their father and Ambrose hands out carefully counted treats. Meanwhile, a man dressed as Frankenstein's monster snatches candy from some of the children trick-or-treating with Julie. Leaving Ambrose alone with Natalie, whom he seems to be developing a crush on, Adrian investigates the candy theft and discovers that all of the victims received candy from "the special man" (Ambrose). He also finds a clove cigarette linking the two crimes. When Julie convinces Monk to take her out trick-or-treating again because she hardly got any candy, he comes across another clue: a dead pigeon he believes is the same one the captain shooed away. He convinces a reluctant and skeptical Stottlemeyer to have the pigeon autopsied and the pieces of the puzzle fall together.
Season 4 Episode 2 of Monk resulted in a 0.00 rating in the 18-49 demographic.
Former police detective Adrian Monk, whose photographic memory and amazing ability to piece together tiny clues made him a local legend, has suffered from intensified obsessive-compulsive disorder and a variety of phobias since the unsolved hug of his wife, Trudy, in 1997. Now on psychiatric leave from the San Francisco Police Department and working as a freelance detective/ consultant on difficult cases, Monk hopes to convince his former boss, Captain Leland Stottlemeyer, to allow him to return to the force. Stottlemeyer, who wavered between admiration for Monk and annoyance at his eccentricities during the first season, is becoming more of a friend to Monk as the series develops, frequently calling him in to help, as much for Monk's benefit as for his own. However, he knows Monk's limitations as well as his strengths and may still harbor doubts about the wisdom of allowing Monk to carry a gun or subdue a perpetrator. Stottlemeyer's second-in-command, Lieutenant Randall Disher, also seems to be developing both admiration and compassion for the man he once labeled "the defective detective".
Despite flaws and inadequacies all around, the three are becoming an increasingly effective team, with additional help from Monk's personal assistant. From the double-episode pilot through the first half of season three, Monk was aided by his nurse, Sharona Fleming. But in the tenth episode of the third season, Sharona was replaced by a new assistant, Natalie Teeger. Like Sharona, a divorcee with a son named Benjy, Natalie is a single parent, a widow with a daughter named Julie. Unlike Sharona, Natalie is not a nurse but a former bartender with a fresh perspective on "Mr. Monk", as she still addresses her new boss.