Harper's Island was once the scene of a gruesome series of murders. Now, seven years later, family and friends gather on the island for a wedding, but one by one they begin to die.

Rampaging serial killers leave carnage in their wake as their next victims fight to stay alive in this horror anthology series. The first season, "The Executioner", centers around Sarah Bennett who, with husband Dylan, moves back to the town of her birth, Waterbury, and into her parents' former home where them were murdered. The second season, "Guilty Party", is centered on a group of former summer camp counselors who return to an isolated campground in order to bury the sins of their past, before being targeted, one by one, by an unknown killer. The third season, "Solstice", centers around a group of neighbors who are targeted by a mysterious killer known as "The Druid" during the summer solstice period, due to their complicity in not saving a murder victim, in the previous year, who later wounded up being killed in front of their apartment complex.

Hostage negotiator Eric Beaumont understands criminals better than they do, and uses his insight into human behavior to resolve the most difficult kidnap and ransom cases. Despite the stakes, Eric refuses to resort to violence, even when confronted by some of the most dangerous criminals in the world. While Eric’s considerable powers of manipulation make him the best at what he does professionally, they often complicate his relationships with family, friends and colleagues.