Hill House is a mansion in a location that is never specified but is between many hills. The story concerns four main characters: Dr. John Montague, an investigator of the supernatural; Eleanor Vance, a shy young woman who resents having lived as a recluse caring for her demanding disabled mother; Theodora, a flamboyant, bohemian artist; and Luke Sanderson, the young heir to Hill House, who is host to the others.
Dr. Montague hopes to find scientific evidence of the existence of the supernatural. He rents Hill House for a summer and invites as his guests several people whom he has chosen because of their experiences with paranormal events. Of these, only Eleanor and Theodora accept. Eleanor travels to the house, where she and Theodora will live in isolation with Montague and Luke.
Hill House has two caretakers, Mr. and Mrs. Dudley, who refuse to stay near the house at night. The blunt and single-minded Mrs. Dudley is a source of some comic relief. The four overnight visitors begin to form friendships as Dr. Montague explains the building's history, which encompasses suicide and other violent deaths.