On the very first night, Dr. Montague finally reveals the nature of their visit and goes through the history of the house. It's been standing about 80 years, and it was first built by the Crain family. Though some deaths have occurred under the roof, it's not a space of murder and deceit. As Montague explains, the house isn't haunted in the traditional sense of the word. Instead, it gets inside your head and drives you crazy.
The core four characters experience some strange, indirect hauntings as their stay continues. Without spoiling too much, there are loud knocks, jiggling door handles, strange writing on the walls — the list continues. Once the weekend guests arrive, there are spirit readings with a planchette — which is basically what comes with Ouija boards nowadays, plus with a pencil attached.
Eventually, it becomes clear that the house is possessing Eleanor and affecting her more than any of the other guests. At times, it seems like whatever's haunting her may be a product of her imagination and that she's going insane. In other moments, the paranormal occurrences seem very real.