Two things happen almost simultaneously in this novel. First, the woman who runs the largest band of child pickpockets and beggars in London asks Alfred to look into the disappearance of several of her lads. More boys are disappearing than usual. Then, a learned gentlewoman wants to accompany Alfred and Birdie on their jobs because she has studied every book she can find about these demonic beings. She makes it worth their while - at first.
Well, that's all I can tell you without spoiling the book for you. Just know that there are some evil doings in here and some treachery - of the human kind. And Birdie and Alfred get their world shaken up and thrown around.
How to Catch a Bogle by Catherine Jinks Check a library or bookstore near you. I hope the next book in this series comes out soon.