Is Dr Karswell (Niall MacGinnis) in possession of the ability to summon demons and a servant of Satan? Well Professor Harrington (Maurice Denham) thinks so but after he goes and challenges Karswell in his creepy mansion he is apparently killed by the Horned One. Or maybe it's just an electric shock?
Dr Holden (Dana Andrews) is on his way over from the US and he is sceptical about everything involving witchcraft. Harrington's niece Joanna (Peggy Cummins) assists him in his investigation into what really is going on. Then Dr Holden finds he is "marked for death"... a rune covered parchment passed onto Holden by Karswell. Only by giving Karswell the parchment back can Holden survive.
Superbly creepy Satanic horror. The film is full of atmosphere and dark horror imagery. Dr Karswell is a tremendous character, dripping evil one moment and the mundane the other.