Cillia Ward returns in her 2nd book of her own series that takes her to the bowels of the Earth to save a friend. She and her team consisting of: Captain Gordon Lewis, and ex-artillery man from the Queen's army as well a heightened-challenged gruff, Major Heathcliffe Kraytor, the Clockwork Butler, made of metal and ex-soldier himself, as well as Herbert, the talking Lemur, engage in any and all mysteries that pop up in London, England, circa 1910. Also, you will find a secondary story dealing with a partial, early origin of sorts for Cillia.