Picked up at the Red Ballooon in Minneapolis last summer.

This is an almost book: almost super clever and almost really funny. It's a Victorian madcap adventure, filled with flying machines (I did love that a girl was being scientific), bad guys, funny dogs and funny kids. It's a sequel to a book I haven't read--two girls, including one Asian princess, have escaped from a horrible British girls' school. In this novel, the faceless fiend is after the princes, and adults and kids do all sorts of crazy things to save her.
Parts of it I really enjoyed, but not enough to seek out the first book or see if there are any sequels.