The Twelve Maidens are Neolithic stones, somewhat smaller than Stonehenge's, on the peak of Maiden Tor, the scene of black magic rites. The magic on Maiden Tor is so black that it blots out all signs of life on the Biodar, a radar that picks up ""life signals"" in the area surrounding the secret research unit on the Devon moors. Margaret, a researcher with psychic gifts, is taken in by the naked white magicians, initiated as a white witch, and helps fight the sex-and-chickenblood rites of the naked black magicians. Bare skin gives off supernovas of big magic. A restrained science-gothic, this is a few cuts above panting banality but far from first-rate.