It is 1896, and Sherlock Holmes is presented with his strangest case yet. While attempting to prove the existence of telekinesis to a scientific society, a self-proclaimed psychic named Kellway disappeared from a locked room, in front of several witnesses. With a £10,000 reward at stake, Holmes is convinced Kellway is a charlatan - or he would be, if he had returned to claim his prize. But as Holmes and Watson investigate, the case only grows stranger and more difficult, as they have to contend with the interference of an 'occult detective'. Then one of the society's members is murdered, and Kellway himself reappears. But he is not the same man who vanished...