Dr. John Holden, an American psychologist, travels to England for a conference on the paranormal, intending to debunk what he believes to be a fraudulent cult led by Dr. Julian Karswell. Upon arrival, Holden learns that his colleague, Professor Harrington, who shared his skeptical views, has died under mysterious circumstances. Despite the growing suspicion and fear from those around him, Holden remains resolute in his disbelief. He is soon approached by Harrington's niece, Joanna, who is convinced that Karswell is behind her uncle's death and implores Holden to investigate.

Holden becomes entangled in a series of inexplicable events and eerie phenomena as he delves deeper into the cult's workings. Karswell warns Holden that a fatal curse is now upon him, revealed through an ancient parchment covered in runes. Skeptical yet increasingly unnerved, Holden races against time to uncover the truth about Karswell's power and the reality of the curse before it claims another victim. The tension escalates as Holden's rational worldview is challenged by the creeping possibility of supernatural forces at play.