The legendary Loreley has been living for centuries in a grotto beneath the river Rhein in Germany. Every night when the moon is full, she turns into a reptile-like creature craving for human blood. When one girl after another of a nearby boarding school is killed by her, a hunter named Sigurd is engaged to kill the monster.
Their sexually dissatisfying marriage life changes when Paula discovers her latent masochism after raped by her husband, Fernando. She welcomes Celia, a vicious young woman whom she has met in a park and, in the end, Paula ends up officiating as a dog of both, while Celia will eventually dominate the situation.
