A calculating killer who calls himself The Teacher is taking on New York City, killing the powerful and the arrogant. Discovering a secret pattern to The Teacher's lessons, Detective Mike Bennett realizes he has just hours to save New York from the greatest disaster in history.

"A woman awakes in the morning to find that someone has picked her apartment's supposedly impregnable door lock and rearranged personal items, even sitting beside her while she slept. The intrusion, the police learn, is a message to the entire city of carnage to come. Lincoln Rhyme and Amelia Sachs are brought in to investigate and soon learn that the sociopathic intruder, who calls himself 'the Locksmith' can break through any lock or security system...

Manhattan D.A. Alex Cooper investigates the murders of three victims while dodging infuriated gang members packing heat. Her interrogation skills lead to someone with a twisted obsession concerning the military, and things grow increasingly dangerous when the chase leads to a chain of small, abandoned islands around New York harbor.