A woman's body is found in marshland outside LA. By the next morning the police have discovered the decaying corpses of three more women, all prostitutes except for the most recent who seems out of place in the marsh's grim tableau. Psychologist Alex Delaware assists homicide detective Milo Sturgis with the case. At first it seems a devilish serial killer is prowling LA's streets, but when a new murder deviates from the pattern, Alex and Milo must consider an even more sinister mind at work.