An allegedly haunted house, built 90 years ago, has claimed numerous lives and created the fear surrounding it. In the modern day, Hill House has been inherited through its original family, but now remains uninhabited.
Dr. John Markway (Richard Johnson) is determined to find out the source of the haunting behind the house. He invites numerous people who have already had experiences with the supernatural, but only two show up - Eleanor Lance (Julie Harris) and Theodora (Claire Bloom). They are accompanied by another potential heir Luke Sanderson (Russ Tamblyn).
After spending a few nights in the house, Markway is convinced of the haunting, but his experiment appears to be having a bad effect on Eleanor.