Sherlock Holmes mystery from the author of Snakeskins and Hope Island. 1896. A white-haired, bearded client arrives at Baker Street and is recognised immediately by Holmes. This client is being threatened by someone unknown to him through curious means: doctored lecture slides, and Watson realises this is Eadweard Muybridge, pioneer of animal and human locomotion photographs, who presents his motion-study animations to interested parties through his zoopraxiscope device. When the two attend one of his lectures they find disturbing alterations to Muybridge's slides he swears he did not put there and as they investigate further, discover murder and conspiracy with the fledgeling arts of photography and cinema at its heart...