I'm over this series. I really liked Rouletabille in the first book but learning more of his back story made him less interesting. Also, the contrivances just piled up to a silly extent and it did that annoying Sherlock Holmes type thing where nothing is explained until a big info dump at the end.

The villain was overly cartoonish MAJOR SPOILER

I don't care how much of a 'Master of Disguise' he was, he would not have been able to impersonate someone and fool his wife, father in law and friends

and the new characters were boring (with the exception of Edith and the russian Prince, I wanted more of them!)

Whilst I love any story set in Imperial Russia, I'm going to give the next in this series a miss.