On the eve of May Day, dark elemental forces begin to disturb the village of Devil's End as the Master summons the demon Azal: unexplained murders, a stone gargoyle come to life, and a nigh-impenetrable infernal energy dome. With the Master fully prepared to destroy the Earth, the Doctor and UNIT - aided by a benevolent practitioner of witchcraft - battle the wicked rites of a secret science wielded by an alien from another world.
Jon Pertwee , Katy Manning , Nicholas Courtney , Richard Franklin , John Levene , Roger Delgado , Damaris Hayman , Don McKillop , David Simeon , Gerald Taylor
BBC
