Christine gets her big chance at modelling when she applies at Sybil Waite’s agency. Together with Christine’s sister Betty they go to a castle for the weekend for a photo shoot. Sybil has lured Christine to the castle for more than modelling: she is recruiting a virgin for induction into a witch’s coven, led by the owner of the castle, Gerald. To their surprise, Christine is more than eager to join the coven, but begins her own secret battle for control.

After a mysterious explosion leaves a large fissure in the ground, two young boys are confronted by an unknown phenomenon that inflicts severe radiation burns on one of them. There follows a spate of attacks at radiation establishments as the inexplicable life-form plunders radium stores. Dr Royston, an expert in atomic research, is brought in to explain and curtail the activities of this alien creature before it causes disaster.