The penultimate Hammer film of the period is a muddled mixture of post-Exorcist shock and the more traditional House of Horror style. Based on Dennis Wheatley's occult bestseller (he hated it), the plot has Satanist Christopher Lee coercing nubile nun Nastassja Kinski into having the Devil's offspring, while Richard Widmark, a writer specialising in the supernatural, tries to foil his plan. Although skilfully directed by Peter Sykes - with a firm tendency towards a trendy fragmented narrative and explicit exploitation - this misguided attempt to update Hammer's image is more likely to be remembered for teen Kinski's unashamed early performance than anything else.

An American occult novelist battles to save the soul of a young girl from a group of Satanists, led by an excommunicated priest, who plan on using her as the representative of the Devil on Earth.