Late 1895, and Sherlock Holmes and his faithful companion Dr John Watson are called upon to investigate a missing persons case. On the face of it, this seems like a mystery that Holmes might relish as the person in question vanished from a locked room. But this is just the start of an investigation that will draw the pair into contact with a shadowy organization talked about in whispers, known only as the 'Order of the Gash'. As more and more people go missing in a similar fashion, the clues point to a sinister asylum in France and to the underworld of London. However, it is an altogether different underworld that Holmes will soon discover as he finds himself face to face not only with those followers who do the Orders bidding on Earth, but those who serve it in Hell: the Cenobites.