After an accident that nearly kills her, Emily and her husband, Freddie, move from London to a beautiful Dartmoor country house called Larkin Lodge. The house is gorgeous, striking—and to Emily, something about it feels deeply wrong. Old boards creak at night; fires extinguish; and books fall from the shelves—all of it stemming from the terrible presence she feels in the third-floor room.

But these things happen only when Emily is alone, so are they happening at all? She is still medically fragile. Her post-sepsis condition can cause hallucinatory side effects, which means she cannot fully trust her senses. Freddie does not notice anything odd and is happy with their chance at a fresh start. She, however, starts to believe the house is haunted by someone who had been murdered in it even though she can find no evidence of a wrongful death. As bizarre events pile up and her marriage starts to crumble, Emily becomes obsessed with discovering the truth about Larkin Lodge. But just as the house has secrets so do Emily and her husband.