Eleanor "Nell" Vance, an insomniac, has cared for her invalid mother for 11 years, sharing a Boston apartment with her. After her mother dies, Nell's sister Jane and her husband Lou inherit the residence and eject Nell to prepare for a sale. As she faces homelessness, Nell accepts an invitation to participate in an insomnia study by Dr. David Marrow at Hill House, a secluded manor house in the Berkshires of western Massachusetts. At the house, she meets Mr. and Mrs. Dudley, an eccentric pair of caretakers. Two other participants arrive: Luke Sanderson and the glamorous Theodora ("Theo"), along with Dr. Marrow and his two research assistants. Unknown to the participants, Dr. Marrow's true purpose is to study the psychological response to fear, intending to expose his subjects to terror.
The film takes place in an isolated manor on the island of Jersey, off the British coast. In this house lives Grace (Nicole Kidman) and her two children, the tremulous Nicholas (James Bentley) and the cheeky Anne (Alakina Mann). To the house one day come three servants, who are responding, or say they are responding, to Grace's advertisement for domestic help. There are vacancies because the previous servants decamped in the middle of the night without a word of notice. The three new applicants have the advantage of being familiar with the house.