This is a middle-grade book that feels like a middle-grade book. That is neither a good thing nor a bad thing. It did mean I had to keep the target age in mind as I was reading it, because it never really engaged my adult-side brain. But as a children's fairy tale, it's sweet and simple and occasionally clever, with a wonderful protagonist and some really inventive worldbuilding.
The story is simple, as fairy tales are. Liza's younger brother, Patrick, wakes up different one morning. She quickly ascertains that his soul has been taken by the evil Spindlers, spiderish beings who live Below. Her parents don't believe her, so Liza must go alone to the Below and try to bring her brother's soul back.
She's accompanied on her quest by a rat she meets there named Mirabelle, and really, this was where immersion in the book sort of ground to a halt for me. Liza spends a lot of time judging and being kind of rude to Mirabelle, who in turn isn't that nice and doesn't seem terribly happy to be accompanying Liza most of the time. About the halfway point, I found myself wondering "why doesn't this rat just leave Liza and her commentary at the side of the road? I would be sorely tempted." At which point, the simplest answer seemed to be that Mira had other reasons to be along. Which rendered the one potentially thrilling, surprising thing in this book - the betrayal - somewhat toothless.
In the end, I felt like this was a book that didn't know what it really wanted to be. A girl with apparently no friends except her younger brother and babysitter, who has parents whose sum characterization seems to be "harried," goes to a mystical world on an epic quest and comes back more or less unchanged by the experience. She's smart and observant, she just never really gets to shine. I finished the book with one major thought - what was the point? Who or what had changed?
But I suspect that for younger readers, it will work perfectly well, and it's not bad. Just, in the end, kind of empty.