One woman's heartache and determination to find her missing brother leads to the stunning discovery of one of the most chilling serial killer cases in history. In a riveting character-led narrative full of unimaginable twists and turns normally reserved for fiction, detectives discover two depraved men who killed at least 25 people in pursuit of their macabre sexual fantasy to enslave young women at a remote cabin in the woods, and who documented their horrifying crimes. All these years later, mystery still swirls around the facts of this case and the possible involvement of a third person, whose story the show will seek to uncover.