The Devil Rides Out
Richard Matheson (screenplay), Dennis Wheatley (novel)
Christopher Lee as Duke de Richleau, Charles Gray as Mocata, Leon Greene as Rex van Ryn, Patrick Mower as Simon Aron, Paul Eddington as Richard Eaton
The Duc (Duke) de Richleau and his friend Rex van Ryn learn their mutual friend, Simon Aron, is getting very deep into a group of Satanists. They are determined to free their friend from the peril he is increasingly falling.