The attic room is an integral part of the story and plays several parts in it, including as an important symbol. When Millie first arrives at the Winchesters’, she’s struck by the contrast between the sparseness of the attic room and the opulence of the rest of the house. This points to The Seen and the Unseen theme. The remainder of the house, which is frequented by people outside the family and is beautifully and expensively furnished; this mirrors how Andrew and Nina’s marriage is presented to the outside world. The room in the attic represents the truth of their marriage—that is, Nina’s secret torture at Andrew’s hands, away from the eyes of the world.

Millie feels unsettled by the room almost instantly upon entering it, only later realizing that it’s because the room locks from the outside. On her very first night, the doorknob sticks, foreshadowing revelations about what truly happens in the room, and what will eventually happen to Millie there too. Despite the door eventually opening, Millie continues to feel a sense of foreboding about the room. Thus, the space helps maintain the narrative’s tension and suspense.

Also symbolic is that the room looks out onto the backyard, a space of the home to which visitors are usually not privy.