Sierra Barter begins investigating her step-grandfather Jim by reaching out to family members, some of whom she had not spoken to in years. By interviewing Jim's ex-wives, children, and stepchildren, Sierra begins to put together a horrifying image of the man her step-grandfather was and the terror that he inflicted on his own family.
Sierra’s uncle shares a disturbing story further implicating Jim and a private investigator urges Sierra to find evidence. After Sierra searches through family storage, she learns the truth about a night that changed her family forever, and in turn, takes her investigation into a different direction.