New York City, 1896. Hypocrisy in high places is rife, police corruption commonplace, and a brutal killer is terrorising young male prostitutes.

Unfortunately for Police Commissioner Theodore Roosevelt, the psychological profiling of murderers is a practice still in its infancy, struggling to make headway against the prejudices of those who prefer the mentally ill — and the «alienists» who treat them — to be out of sight as well as out of mind.

But as the body count rises, Roosevelt swallows his doubts and turns to the eminent alienist Dr. Laszlo Kreizler to put a stop to the bloody murders — giving Kreizler a chance to take him further into the dark heart of criminality, and one step closer to death.