The first death, Elliot K.

All his life, the special agent of the FBI Mercy Kilpatrick followed the covenants of the survivors - a closed community preparing by the end of the world. But when a cruel serial killer appears in her hometown, these rules begin to work against her. 15 years ago, Mercy suddenly broke off her relationship with her family and escaped from the commune. It's time to return and look into the face of your past. The elusive killer nicknamed the "cave man" one after another kills the survivors. Local hostility towards strangers and government makes Mercy an ideal agent. Together with the chief of Police Truman Daily, they begin to investigate. The new partner sees that, having returned to his native lands, the FBI specialtygent is nervous and something hides. If everyone finds out what she did, it will destroy her career, and perhaps her life...