Classic slice of 1950s psychological horror. Dana Andrews stars as American psychologist Dr John Holden, who arrives in London to attend a paranormal psychology symposium with the aim of exposing devil cult leader Julian Karswell (Niall MacGinnis) as a charlatan and a fraud. On his arrival, Holden learns that the leader of the symposium, Henry Harrington (Maurice Denham), has suddenly died in mysterious circumstances - but Holden, a hardened sceptic, refuses to believe that Karswell could have had a hand in this, and accepts an invitation to stay at Karswell's estate along with Harrington's niece, Joanna (Peggy Cummins). Once there, however, a series of strange occurrences begins by which even the sceptical Holden becomes disturbed...