Deep in Appalachia, Pastor Lemuel Childs (Walton Goggins) presides over an isolated community of serpent handlers, an obscure sect of Pentecostals who willingly take up venomous snakes to prove themselves before God. As his devoted daughter Mara (Alice Englert) prepares for her wedding day under the watchful eye of Hope Slaughter (Olivia Colman), a dangerous secret is unearthed and she is forced to confront the deadly tradition of her father's church.