Toby McClift (Peter Gadiot) is the son of a strict preacher (Roger Tebb) who continually warns Toby that he must never ever fall in love or have anything to do with love. Despite these strict warnings, Toby falls in love with Katie (Jytte-Merle Böhrnsen) and makes plans to meet up with her in a cemetery one night. Just as they are to meet, Katie is swept away by a demonic beast and is never seen again. Toby tries to convince everyone that her disappearance is due to a beast, but nobody believes him, least of whom is his father, and he's placed in a mental institution for the next six years. Once he's released he takes a job in an old castle serving as a tutor for Laura (also played by Böhrnsen), the niece of the elderly Lady Wallace (Jeanette Hain). Toby is struck by how much Katie and Laura look alike, to the point where he's certain that the two are one and the same. He's saddened when Laura claims not to know him, but becomes intrigued by how contradictory her nature is, as she is both sensuality and innocence. At the same time Toby is increasingly unnerved by how strange everything is in the house, including the actions of Lady Wallace's butler Mortimer (Klaus Tange) and several increasingly bizarre visions. He also notices that the longer he stays in the house, the younger Lady Wallace seems to appear. Eventually this becomes too much for Toby and he unsuccessfully tries to perform an exorcism on Laura, convinced that she is being possessed by Lady Wallace. Humiliated by his failure, Toby tries to leave but is stopped by Laura, who confesses that she is a witch that requires a pure, innocent being in order to be young forever and that she needs Toby in order to accomplish this.