Months after escaping a brutal kidnapping, Meg travels with her husband, Scott, to his family’s isolated compound in Cape Cod, hoping the early winter quiet will give her space to recover and for them to reconnect. Shortly after they arrive, however, the couple discovers they are not alone on the property. Scott’s charming but overbearing cousin, Madelin, is staying next door. To Meg’s surprise, the two are quite close and soon Madelin's presence is inescapable. With each passing day Meg and Scott’s already fragile relationship begins to fracture, while Meg is haunted by vivid nightmares, visions of an old woman lurking in the woods, and a growing suspicion that Scott and Madelin are hiding something from her. As the tension in the house grows, Meg begins to act out in increasingly reckless ways, setting into motion a series of disturbing events that shatters the thin barrier of civility between her and the cousins. Subtle manipulation gives way to violent confrontation as Scott and Madelin reveal their troubling history and Meg learns the truth about her abduction.