Iris, the imaginative young daughter of Don and Heather, is returning to Maine with them for a much-needed vacation. But Heather’s job delays her, so Don and Iris arrive first, moving into a rental house with an old trunk at the end of the hall — a trunk that cannot be opened. Don and Heather are fighting, and when they can’t pay enough attention to Iris, something else can. But is it inside her head or inside the box?