After several years of living with a cult, Martha (Elizabeth Olsen) finally escapes and calls her estranged sister, Lucy (Sarah Paulson), for help. Martha finds herself at the quiet Connecticut home Lucy shares with her new husband, Ted (Hugh Dancy), but the memories of what she experienced in the cult make peace hard to find. As flashbacks continue to torment her, Martha fails to shake a terrible sense of dread, especially in regard to the cult's manipulative leader (John Hawkes) .