December. The night of the full, cold moon. A young man is found dead in lower Manhattan, the first in a series of victims of a man calling himself the Watchmaker. This killer's obsession with time drives him to plan the murders with eerie precision. Lincoln Rhyme, Amelia Sachs and the rest of their crew are brought in to handle the case and stop the Watchmaker. But the investigation sets into motion clockwork gears of its own, with consequences for people and events that will endanger not only many lives, but Lincoln's and Amelia's future together.