‘Watson,’ Sherlock Holmes proclaimed, ‘you know very well that it was one of those cases where I felt obliged to circumvent the law ... I credit you with sufficient discretion not to expose me to a prosecution for murder ...’
Thus the great consulting detective referred, in an uncharacteristically nervous manner, to the case of the tobacco millionaire and the Glastonbury Fragment, one of the most bizarre investigations of Holmes’s and Watson’s long partnership.

In the spring of 1895, Colonel John Vincent Harden, an American inventor of an ingenious camera of great potential importance to criminal investigators and archaeologists, was the object of anonymous threats to leave Britain, escalating to the abduction of his son, Jay. Behind this criminal activity, Holmes detected the hand of Drew, his old enemy’s, Professor Moriarty’s, lieutenant, an ex-Scotland Yard detective and worshipper of Demeter, the goddess of fertility.
Drew suspected that Harden’s stereoscope could uncover the mystery of a perverse religious cult, a priceless treasure which, if possessed, Moriarty believes, would give him power over the whole world.

The inevitable conflict between the Baker Street Irregulars and the henchmen of the vile professor was joined one dark night on the Welsh borders where the forces of evil were once again held at bay by the redoubtable detective and the devoted doctor.