I echo the sentiments of other reviewers: this is very different from the first book.
First of all, this book takes place almost entirely in France, during the time of Napoleon III, where Katharine goes to search for Lane. Second of all, the story takes place over a wider area, whereas the first book took place in a confined area of a small town.
Intrigue ensues, with shady characters, royal secrets, and the like. New characters pop up, who I quite like and hope to see again, if there is another book, that is.
I can't guess what a third book would be about. This book didn't end with a question mark like the first book, which I knew would have a sequel. I guess we'll just have to see.