A young woman is stalked by a bloodthirsty cult of Satanic worshippers. To escape from the killers, Madelyn Rose (Samara Weaving) hides in her father's remote cabin in the woods. When members of the cult start brutally murdering Madelyn's close friends and loved ones in an effort to lure her out of hiding, Madelyn discovers why the cult is targeting her and learns a terrifying and sinister secret about her past.