Mara Childs, portrayed by Alice Englert, is the daughter of a Pentecostal pastor, raised in a secluded community nestled in the heart of Appalachia. To the delight of her father, Walton Goggins, she finds herself in a serious courtship with Garret, embodied by Lewis Pullman. However, unbeknownst to her family and the congregation, Mara harbors a secret: she is pregnant with the child of Augie, played by Thomas Mann, who has distanced himself from the church.
Feeling the weight of expectations from both her community and her father, Mara reluctantly agrees to Garret's marriage proposal. Her father, Lemuel, leads a particular sect known for its snake-handling rituals. When a minor tragedy occurs during one of these rituals, causing a death, Lemuel is warned about a police investigation looming overhead. In a misguided attempt to shield his congregation, he allows Garret to take the fall for the snake-related incidents, resulting in Garret losing his job.
Before the wedding can take place, Mara's purity is assessed by Hope Slaughter, Augie's mother. Hope discovers that Mara is not only not a virgin but is also expecting a child. Compassionately, she chooses to keep this information from Lemuel and Garret but informs Augie, urging him to seek redemption for his actions.
In a desperate move to reconnect with Mara, Augie attends church, masking his true intentions under the guise of a spiritual transformation. Lemuel, obliviously supportive, encourages Augie to participate in the snake-handling ritual, leading to a bite that puts Augie's life at risk. When he pleads for medical assistance, both his family and Lemuel deny him and he attempts a gruesome self-treatment. This dark moment sets the stage for a private encounter between Augie and Mara, which is interrupted by Garret, who issues a stern warning to Mara to stay away from Augie.
The subsequent day brings more turmoil when Mara confides in her friend Dilly about her pregnancy, leading Dilly to disclose this to Garret. In a fit of rage, Garret attempts to assault Mara but is thwarted by Lemuel, who, in a chilling confrontation, learns of Mara's situation, thanks to Garret's revelations.
Desperate to "cleanse" his daughter, Lemuel insists that Mara handle a snake in church, while Augie's concerned parents decide to perform an amputation at home, knowing their son’s life hangs in the balance. Miraculously, Mara survives her harrowing test, gaining her father’s approval in the process. Yet, in a moment of clarity, she chooses to leave the oppressive confines of her father's influence to care for Augie, who is suffering from the aftermath of his surgery. With the blessing of Augie's parents, Mara embarks on a journey with Augie, vowing to stand by him and support him through adversity.
