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

Reowned criminalist Lincoln Rhyme is pitted against Amelia Sachs, his own brilliant protegee, as they disagree on the analysis of a crime they began working together.