Lincoln Rhyme and Amelia Sachs return to New York City from their honeymoon in Italy to discover a killer is terrorizing New York City. Dubbed the Fiancé Killer, their latest foe targets newly engaged couples by following them into jewelry stores, ending the couples' lives just before they can purchase the ring that symbolizes the future that will never be theirs. As panic grips the city, Rhyme and Sachs quickly spring into action with the full weight of the NYPD backing up the pair's forensic brilliance. But the killer proves elusive, and his agenda is much more than first meets the eye. Soon it becomes clear that the closer Rhyme and Sachs draw to the killer, the closer the killer draws to them. And their foe soon notices that there's something especially arresting about the ring Rhyme gave Sachs--something that could cost both of them their lives.