June 1897. It's been a year since Dr. Laszlo Kreitzler tracked down a brutal serial killer using revolutionary methods of criminal psychiatry. He and his faithful assistants, including the well-known reporter John Moore and the indomitable Sarah Howard, are back to business as usual. But when the Spanish diplomat's wife desperately asks Sara for help, the friends reunite to find her kidnapped young daughter. During the investigation, they make a discovery so terrible that it is hard to believe in its reality...