The husband of Monk's former assistant, Sharona, has been arrested for murder. Now back in San Francisco, she's ready to reclaim her place in Monk's life — much to the chagrin of his current assistant, Natalie. While Monk tries to maintain a delicate balance between the two women, he discovers a few unsettling snags in the case against Sharona's husband, and may be up against a killer who not only understands him, but is one step ahead.

Adrian Monk is actually doing well lately. He is solving murders as fast as they come, and he has been noticeably less compulsive—he doesn't count his morning Wheat Chex until they're in the bowl. Progress is progress, and Monk knows he owes it all to his therapist, Dr. Kroger. So when Dr. Kroger attends a conference in Germany, Monk ends up in trouble. He can't tie his shoes, forgets how to swallow, and loses track of his blinking. Desperate

Captain Leland Stottlemayer is faced with budget cuts and trims Monk's services as an expense. Though he insists it's nothing personal, when Monk's offers to help for no charge are declined, he and Natalie suspect otherwise. But Monk is too compulsive to stop investigating. So when Stottlemayer is arrested for the killing of another cop with overwhelming evidence against him, he must turn to the only detective who can prove his innocence.