A secret society issues a demand on the British government for £100 million with the threat that, if they are denied, they will begin destroying all the major cities of Europe. At first, the demand is ignored as a hoax or the ravings of madmen, then suddenly a large part of London is reduced to ashes by means of a chemical explosive unknown to all of the nation’s top scientists.
Meanwhile, a mysterious French count ingratiates himself with an English cabinet member and, under the guise of removing them to a place of safety outside of London, abducts his daughter and son-in-law.
There are tantalizing clues scattered about and the corners of the mystery are chipped away, but don’t expect some detective character to step forward and explain everything at the end. The characters who survive learn very little of what has happened or why it happened and neither does the reader.
The novel begins as would a traditional mystery, but as it progresses, it becomes more of a gothic horror.