THE DEVIL RIDES OUT

Set in London and the south of England in 1929, the story finds erudite Nicholas, Duc de Richleau, investigating the strange actions of his protegé, Simon Aron, the son of a late friend, who has a house replete with unusual markings and a pentagram. He quickly deduces that Simon is involved with the occult. De Richleau and his friend Rex Van Ryn manage to rescue Simon and another young initiate, Tanith, from a devil-worshipping cult. During the rescue, they disrupt a May Day ceremony on Salisbury Plain, in which the Devil appears under the guise of the "Goat of Mendes".

They escape to the country home of de Richleau's niece Marie and her husband Richard Eaton. They are followed by the group's leader, Mocata, who has a psychic connection to the two initiates. After visiting the house while de Richleau is absent to discuss the matter and an unsuccessful attempt to influence the initiates to return, Mocata forces de Richleau and the other occupants to defend themselves through a night of black magic attacks, ending with the conjuring of the Angel of Death. De Richleau repels the angel, but it kills Tanith instead (for, once summoned, it must take a life).

His attacks defeated, Mocata kidnaps the Eatons' young daughter Peggy. The Duc has Tanith's spirit possess Marie in order to find Mocata, but they only are able to get a single clue, until Rex realizes that the cultists are at a house he visited earlier. Simon tries to rescue Peggy on his own, but he is recaptured by the cult. De Richleau, Richard, and Rex also try to rescue her, but they are defeated by Mocata. A powerful force (or Tanith herself), however, starts controlling Marie and ends Peggy's trance. She then leads Peggy in the recitation of a spell which visits divine retribution upon the cultists and transforms their coven room into a church.

When the Duc and his companions awaken, they discover that the spell has reversed time and changed the future in their favour. Simon and Tanith have survived, and Mocata's spell to conjure the Angel of Death has been reflected back on him. Divine judgment ends his life, and he is subject to eternal damnation for his unholy summoning of the Angel of Death. De Richleau comments that it is God to whom they must be thankful.

The heroes confront Mocata and his cult in a final occult showdown. A spell reverses time, saving Simon and Tanith, while Mocata is destroyed by divine retribution.

The film’s climax underscores the power of faith and the ultimate downfall of those who meddle with dark forces. Through divine intervention, the timeline is reset, sparing the innocents and punishing the villainous Mocata, reinforcing the classic Hammer theme that evil is both seductive and self-destructive.