Morgan Russell, 30, is completing her thesis on victim psychology at New York's John Jay College of Criminal Justice and newly engaged to Bennett, a man more possessive than those she has dated in the past, but also more chivalrous and passionate. She returns from class one day to find Bennett brutally killed, and her dogs--a Great Pyrenees, and two pit bulls she was fostering - covered in blood.Bewildered and devastated that her dogs could have committed such violence, she worries that she might suffer from one of the syndromes she studies--pathological altruism: when selfless acts do more damage than good. But when Morgan tries to locate Bennett's parents to tell them about their son's hideous death, she discovers that everything he has told her was a lie. In fact, he fits the clinical definition of a sociopath, and he had several fiances, all believing the same promises he gave Morgan. And then, one by one, these other women are murdered.