Monk takes a job as a substitute high school teacher at Trudy's alma mater to determine whether an English teacher really jumped from a clock tower while committing suicide, or was murdered by her boyfriend, a popular science teacher (Andrew McCarthy).

When a skydiver on vacation in San Macros, Mexico jumps out of an airplane, his chute malfunctions and he dies on impact in the desert. But the coroner finds water in the skydiver's lungs, saying that the boy drowned in midair. Monk is brought to Mexico, where the phrase "don't drink the water" takes on a whole new meaning.

When a ruthless CEO and his wife are lured to an industrial park and are shot dead in their car, Monk connects their murders to a star baseball player's (Christopher Wiehl) quest for the single season home run record.

When a circus ringmaster is shot dead by a high flying acrobat at a restaurant, Monk immediately suspects the man's vengeful ex-wife (Lolita Davidovich) of the murder. But before Monk can find out how the pretty trapeze artist committed the murder with a broken foot, he must get Sharona to overcome her fear of elephants.

Captain Stottlemeyer must take a page from the Book of Monk when his wife nags him into looking into the murder of the world's oldest man. First on-screen appearance of Karen Stottlemeyer (Glenne Headly).

Sharona's sister Gail (Amy Sedaris) lands a part in a local play that any actress would kill for. But when the actor playing her love interest literally dies on stage after Gail apparently stabs him with a real knife that was switched with a prop knife, the police are convinced she's taken her role a little too far. Sharona and her mother (Betty Buckley) urge Monk to step into the spotlight and find the real killer before the curtain falls on Gail for good.

Monk suspects a guy of murdering his sister with a mail bomb. The only problem: his primary suspect is in a coma. Meanwhile, Sharona is visited by her ex-husband Trevor (Frank John Hughes).

When the publisher of the high-powered glamour Sapphire Magazine is strangled and killed on his exercise weights under mysterious circumstances, all clues lead to the infamous swinging party palace, Sapphire Mansion, and the playboy (Gary Cole) behind the magazine. But while a weekend behind the gates of the legendary estate may be every man's fantasy, it is Monk's worst nightmare, especially after his suspect threatens to release embarrassing photos from Sharona's past.

When a rash of unusual attacks and murders strike, Monk is called upon to find the link between the victims and stop the killer before the next murder.

When Monk's paperboy is murdered on his doorstep by a guy looking to steal his newspapers, Monk turns to the pages of the newspaper for clues to solve the baffling crime.

During the investigation into a carjacking over a cherry pie, Adrian is called by his estranged agoraphobic brother Ambrose (John Turturro), who is convinced that his next-door neighbor murdered his wife. Adrian must rebuild his relationship with Ambrose while investigating the neighbor at the same time.

Monk suspects the star (Billy Burke) of a popular CSI-based TV crime show of killing his ex-wife so that he doesn't have to share his enormous paychecks with her.

A law student (Rachel Dratch) offers to get Monk reinstated to the police force in exchange for his help in finding the kidnappers of her beloved grandmother.

A tow truck driver is shot dead by a roadside sniper. His truck then careens off the road and crashes into Karen Stottlemeyer's (Glenne Headly) oncoming van, leaving her in a coma. Monk, most interested by the fact that the shooter and the driver were barefoot, must find out what really happened and keep Leland from doing something that could cost him his badge.

When Randy's mother gets married to an antiques store dealer (Nestor Carbonell), Randy becomes suspicious of his new stepfather and asks Monk and Sharona to look into him.

When a death row inmate is poisoned to death 45 minutes before his scheduled execution, Monk is brought in to find out why and runs into his nemesis, Dale the Whale (Tim Curry), who will offer Monk information about Trudy if he finds who killed the inmate. The suspects, however, are endless, including the prison librarian (Kathy Baker), another inmate (Danny Trejo), and even neo-Nazis.