Energetic occult thriller which overcomes its familiar set up to deliver an adrenaline rush which never lets up. Peter Wyngarde plays an erudite psychology professor on campus at a British university who has a rigid belief in rationality. But after he gets his credulous wife (Janet Blair) to burn her voodoo paraphernalia, his world starts to fall apart.
This is the third version of the novel The Conjurer Wife, and the premise of the scientific mind in conflict with the supernatural has been explored many times; including the similarly titled Night of the Demon. This isn't quite as good, but there is an intelligent script and Sidney Hayers' kinetic direction- plus a rousing score- make it an exhilarating spellbinder.
Wyngarde was a late substitute for Peter Cushing. Which was an advantage as the replacement brought a muscular vitality. Hard to imagine the lean, wan Hammer star being chased around the quad by a paranormal eagle in the rousing climax. Margaret Johnson gives a wonderfully strange performance as the conjurer wife's rival.
There's a transatlantic feel to the production, perhaps because the adaptation was by veterans of The Twilight Zone. The limited sets suggest a small budget but this gives the film a feeling of entrapment, enhanced by the web of noirish shadows. The effects and stunts are fine. There's nothing new here, but it's rarely done as well.