I enjoyed Franny Billingsley’s book Chime so much, that I decided to check out her earlier fiction aimed at children. The protagonist keeps the “folk” at bay in the houses she serves, if she doesn’t she is the first line of defense and suffers intense pain and the possibility of death. She comes to a new estate where the “folk” are much fiercer than what she is accustomed to. She is hiding the fact that she is a girl, because “folk keepers” are not supposed to be female. She discovers other things about herself as she goes along.
Like Chime, the clues to the mystery are all out on display, easy to decipher, IF you know that there is a mystery to be solved, and if you can figure out which is the most important puzzle to solve.
So, you can see that Billingsley has really polished her writing over the years, but the essentials are present in this story.