Lieutenant Vincent D'Agosta is the lead detective on the murder investigation in the Museum of Natural History. D'Agosta is over his head and he is aware of this fact; therefore, when Pendergast comes in, D'Agosta is more than willing to follow his lead. Together, Pendergast and D'Agosta come to the conclusion that the killer might not be human, but might be some kind of creature. However, Pendergast is removed from the case and D'Agosta finds himself forced to follow the orders of Pendergast's less than professional replacement. D'Agosta knows that this man is leading thousands of guests into danger, but does what he can to protect them.