This is book three in the Finishing School series by Gail Carriger. The more I read of this series, the more I love it! It follows a girl, Sophronia, who attends a spy school under the guise of a finishing school. The finishing school is held in a dirigible that floats over steampunk London. Since this book is the third in a series, I don't want to give too much away. But I will say that it involves an airdinghy, a runaway train, multiple werewolves, a sootie or two, and a fabulous costume ball. I highly recommend this book.