In 1888 Dr John Eliot returns to London haunted by the memory of a terrible expedition to a remote Himalayan kingdom, where he had uncovered horrors far beyond the frontiers of science. Yet Eliot's faith in reason is to be tested even further when the body of a friend, drained with blood, is dragged up from the Thames, and another associate goes missing. Eliot's quest to uncover the heart of the mystery reveals a deadly conspiracy, but then, in the lair of an enigmatic Eastern adventuress, he glimpses hints of a truth yet more extraordinary, of dark and terrible pleasures, of a whole new world . . .