Cirrus@Austlit

'Separated from his wife, Watson returns to Baker Street. On the mantlepiece, where Holmes keeps the souvenirs of his latest case, Watson finds a stone bearing a demoniacal, but vaguely familiar figure. While Holmes is out, Gregson arrives with news of an antiques appraiser, Pethebridge, who has apparently shot himself through the heart with a crossbow. They are interrupted by the arrival of a mysterious Arab. Gregson takes Watson to the murder site. Under the body is a photograph of a dying shaman. Holmes arrives on the scene and reveals the probable route of the murderer's arrival and escape, while his and Gregson's ongoing investigations lead to death and Watson coming into possession of another identical stone, and a photograph with a familiar face in it. He is forced into a terrible act to bring a case that begins in his own past, to its end.'

Source: Sherlock Holmes Pastiche Characters (http://www.schoolandholmes.com/summariess.html). (Sighted: 17/7/2014)