Amelia Sachs is chasing a killer through a department store in Brooklyn when an escalator malfunctions. The stairs give way, with one man horribly mangled by the gears. Sachs is forced to let her quarry escape as she jumps in to try to help save the victim. She and famed forensic detective Lincoln Rhyme soon learn, however, that the incident may not be an accident at all, but the first in a series of intentional attacks. They are up against a killer who turns common products into murder weapons, and as the body count threatens to grow Sachs and Rhyme must discover his mission before more people die.