Even though this series is fiction, the author sets the books within the correct timeline of Houdini's travels. The first book, Metamorphosis, featured Houdini in San Fransisco in 1899. This new book finds him in Berlin in 1900.
The author has shared with me the exciting location for book 3, but I will keep that secret for now.
Le Kaiser Et Le Roi Des Menottes can be purchased at Amazon.fr and Amazon.co.uk. It's also available for Kindle in the U.S.