Wow! What a ride! Deaver is a master at plot twists and this one has quite a few... A man known at the Digger randomly shoots up a DC metro station. There is a ransom note for a large sum of money and a threat of more random shootings every 4 hours .... A farmer FBI agent, Parker Kincaid, who is an expert in documents is called in to analyze the ransom note. Lincoln Rhyme, Deaver's popular series character, makes a brief off stage appearance. Puzzles and solving of them are part of the novel's attraction.