Millikan determines that the crime was committed not by a psychopath but by a professional killer of consummate skill and total lack of feeling: "I think that the one who did it is one of the special cases. He's somebody we can't afford to have walking down a street where our families walk."

When Millikan learns that the investigation has come to a complete standstill, he commits himself to an unorthodox decision. The only hope of stopping this killer and ending the bloodshed is to employ Roy Prescott, an expert in the narrow specialty of hunting down murderers through methods the police can't -- and wouldn't -- use.