They say the evidence never lies, but don't tell that to Detective-Sergeant Moby Truax. He'll tell you the evidence could be allowing a killer of women to roam the streets of Baltimore. The evidence is consistent--apparently random female victims, each killed the same way with an identical concentration of cyanide. But DS Truax, a financially strapped cop nearing the end of his career, notices that the profile of the recent victims doesn't match that of earlier targets. He suspects a copycat killer, but his rejection of the lone murderer theory puts him on the wrong side of superiors. As beautiful young women continue to die, Truax is saddled with a partner: FBI Special Agent Frances Vecchio. To Truax she is little more than an attractive distraction, but his bosses see her as a possible savior, turning a blind eye when Vecchio launches her own investigation to catch the monster the newspapers have dubbed the Cyanide Killer. With his pride and his pension on the line, Truax follows the facts no one else sees, but will this chain of evidence lead him to multiple killers, or a murderous deception that is even deadlier?