The story of The Demon Lover begins with a secret society of mystics, in London, magically communicating over great distances with other occultists; so we learn that the society’s magic works, that it’s part of an international group, and that it’s scheming to gain political power at the urging of one member, a man named Lucas. We also see that much of the society is opposed to Lucas and his plots. This leads Lucas, after the meeting is concluded, to hatch a scheme of his own: to find an unsuspecting but psychically-gifted person to serve him as a medium, and through the entranced medium spy on the other members of the society in order to gain greater mystic knowledge.