The husband of Monk's former assistant, Sharona, has been arrested for murder. Sharona, now back in San Francisco, is 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.