The World's Fair.
The Alchemist is how I've come to think of him; he has a passion for the dark side of knowledge, mixing murder and madness with science.
Nellie Bly - reporter, feminist and amateur detective - is in Paris on the trail of an enigmatic killer.
The city is a dangerous place: an epidemic of Black Fever rages, anarchists plot to overthrow the government and a murderer preys on the prostitutes who haunt the streets of Montmartre.
But it is also a city of culture, a magnet for artists and men of science and letters. Can the combined genius of Oscar Wilde, Jules Verne and Louis Pasteur help Nellie prove a match for Jack the Ripper?