A series of deaths have started occurring in New York; some bodies are found gruesomely mutilated while others have the equation "wÎ"z = Cov (w,z) = ÃYwzVz" carved onto their skin. As the police investigate they discover each victim was forced to choose between sacrificing their own life or a loved ones' life. Before long it becomes clear that this perpetrator has suffered a similar fate - so now is coping by seeking a way of solving this philosophical enigma. Can Captain Maclean and his officers (Eddie Argo and his new partner Helen Westcott) stop this killer? Because he/she won't - at least not until he/she gets to the end of the equation.