Blake (Christopher Abbott) is a husband and father living in San Francisco. When his own father disappears and is presumed dead, he inherits his childhood home in rural Oregon. As his marriage to his successful career-driven wife, Charlotte (Julia Garner), begins to fall apart, Blake convinces Charlotte to leave the city and take their young daughter, Ginger (Matilda Firth), to his childhood home for the holidays. But when the family arrives at the farmhouse late at night, they are suddenly attacked by an invisible monster, and to escape the danger, they take refuge inside the farmhouse and seal all entrances, while the monster stalks outside. As they fearfully try to make it through the night, Blake begins to behave strangely and gradually transforms into an unknown monster, forcing Charlotte to decide: Which is more deadly, the terror inside the house or the danger outside?