Powerfully emotional stories tell of people who have been targets of compulsive stalkers. According to the Centers for Disease Control and Prevention, more than 6 million people in the United States are stalked each year, and in most instances, the stalker is someone the victim already knows. The programme's hourlong episodes dramatize actual cases through visceral re-enactments and pointed testimony of victims, family members and law enforcement authorities, revealing what happens when perpetrators can't have what - or who - they want, and stop at nothing to ensure that no one else can either. The chilling accounts probe the mechanics of an obsessive mind and the devastating impact of delusion.