In the late nineteenth-century American frontier, Lizzy Macklin, Caitlin Gerard, and her husband Isaac Macklin, Ashley Zukerman, travel from St. Louis to a sparse corner of New Mexico with the hope of building a settlement. They seek quiet and distance, living largely in solitude until Emma Harper, Julia Goldani Telles, and Gideon Harper, Dylan McTee, arrive from Illinois and settle into an abandoned cabin nearby. The story unfolds out of order, and the opening scenes reveal Emma and her stillborn infant being laid to rest by the three main figures.
Lizzy forms a tentative friendship with the younger Emma, whose marriage to Gideon appears strained. The two women work together to repair the Harpers’ cabin, coax life back into a fallen garden, and plant crops, while Lizzy opens up about the heartbreak of losing her own son, Samuel, to a stillbirth. As Lizzy’s pregnancy progresses, she grows increasingly convinced that a demon may come for her child, especially when Isaac is away, and that fear begins to shadow every night.
Late one night, Gideon rouses Isaac and Lizzy to report that Emma is unwell. The trio arrives at Emma and Gideon’s cabin and finds Emma hiding under a bed, talking to herself and insisting that something unseen is pursuing her. Emma whispers that the thing wants her unborn child and hints at naming the child after either herself or Isaac, a detail that unsettles Lizzy and fuels Emma’s sense of peril. Lizzy, though sympathetic, remains wary of Emma’s visions, even as Emma insists her fears are real.
As Emma nears the end of her pregnancy, she apparently shoots herself in the head with Lizzy’s shotgun. Lizzy attempts a risky caesarean to save the unborn child but fails. Isaac and Gideon bury Emma and her baby and depart to report the deaths, leaving Lizzy alone with her mounting paranoia. The isolation gnaws at her: wolves attack her goats, she shoots her own frightened animal in a subsequent moment of panic, and she experiences eerie lights emanating from the Harper cabin, drawing her to a spectral, unsettled world. The weight of the mystery deepens when she discovers Emma’s diary, which claims Emma despised Gideon and suggests she might be carrying Isaac’s child; Lizzy burns the diary pages in a bid to quiet the fears gnawing at her.
To calm her nerves, Lizzy slips into unconsciousness with chloroform, and the sense of being watched intensifies. A reverend, traveling past the settlement, stops at the Harpers’ cabin, and Lizzy invites him in, asking that he not answer the door after dark. That very night, the reverend knocks frantically, insisting he has been attacked by an unseen entity. He enters, but the next morning his body lies outside, dead. Isaac returns later with a sense that something otherworldly has walked the land, and he and Lizzy exchange a knowing, uneasy look about the encounter with the reverend.
Gideon eventually returns and leaves behind a trunk of books for Lizzy and Isaac. Inside the trunk lies a tract detailing various “demons of the prairie,” a relic that sparks a sharp disagreement between the couple—Isaac fears that reading it could reignite Lizzy’s prairie madness and her fear of the unknown. Soon after, Lizzy experiences a violence beyond her control: she is levitated and slammed against the cabin, her abdomen wounded on a pair of scissors that pierce her skin. She wakes later to find herself tied to a bed, and Isaac, having found Emma’s journal, confronts Lizzy with the truth: she killed Emma out of jealousy.
In the dawn light, Lizzy staggers outside and collapses, her thoughts turning to her pregnancy and to the moment when the reverend first arrived with his tract about the demons of the prairie. The nightmare of the frontier settles around her as she confronts the consequences of fear, desire, and possession on the land she sought to tame.
