De Richleau and his friend Rex Van Ryn manage to rescue Simon and another young initiate, Tanith, from a devil-worshipping cult.

The Duc has Tanith's spirit possess Marie in order to find Mocata, but they only are able to get a single clue, and Rex realizes that the cultists are at a house he visited earlier.

Production began on 7 August 1967, and the film starred Christopher Lee (in a rare heroic role), Charles Gray, Niké Arrighi and Leon Greene.

Christopher Lee had often stated that of all his vast back catalogue of films, this was his favourite and the one he would have liked to have seen remade with modern special effects and with his playing a mature Duke de Richleau.

The A-side of British rock band Icarus's debut single "The Devil Rides Out" was inspired by the advance publicity for the film of the same name.

[10] Paul Leggett, in his study of Terence Fisher's films, describes The Devil Rides Out, despite its occult themes, as a "total conquest of Christianity over the forces of evil".

Christopher Lee is as professionally suave as ever as de Richleau and Charles Gray is suitably sinister as the arch-Satanist; and there is the usual attention to period detail that one has come to expect from Hammer (notably a minor concours d'élégance of vintage cars).

Under Terence Fisher's direction [...] the first 20 minutes are dandy, as a steely aristocrat, played with suave dignity by Christopher Lee, tries to outwit the evil ones[...].

He has built up a suspenseful pic, with several tough highlights, and gets major effect by playing the subject dead straight and getting similar serious performances from his capable cast.

Christopher Lee, here on the side of the angels, swaps his usual fangs/cloak combo for a goatee and occult savvy as the debonair Duc de Richelieu, who's battling to save a friend from Charles Gray's coven of devil worshippers.

Richard Matheson conjures up an intelligent, pacey script to match the menacing atmosphere, while Lee exudes heroic authority in the face of Gray's vulpine villainy.