Jacques Tourneur's Curse of the Demon! American Psychologist, Dr. John Holden (Dana Andrews) arrives in London for a conference only find out his colleague has died under suspicious circumstances. He meets his colleague's niece Joanna  (Peggy Cummins), and together they investigate her uncle's death. Their investigation leads them to satanic cult leader  Dr. Julian Karswell (Niall MacGinnis). They enter a world that makes them question their faith in science.