Dr. Laszlo Kreizler, a brilliant but unconventional alienist, pioneers psychological profiling methods in an era when forensic techniques were still primitive. He creates detailed profiles of the killer by analyzing their actions and attempting to understand their psychology.

The novel exposes the extreme social inequality of 1890s New York, contrasting the wealthy upper class's hidden secrets behind moral facades with the struggling poor. The murders of young prostitutes highlight the era's double standards and moral hypocrisy.

The story centers on an unconventional team including Dr. Kreizler, journalist John Moore, ambitious police secretary Sara Howard, and police commissioner Theodore Roosevelt, who work together to solve the dangerous case.