Like E. Aster Bunnymund, I personally think this book shines best near the end.
The beginning dwells again on impossible, wondrous, great things. I hate to say that it is pretty dull to read about. I'm sorry! I need either inner or outer conflict; I'm not picky. Utopia is actually really boring to read about until something goes wrong. This is probably my adult palate rising up again.
Our newest Guardian of Childhood is Toothiana, who is amazing here. Her backstory sounds like a real, oral tradition, thousand year old fairy tale. The character herself is a fierce warrior queen. She acts a little lonely, very genuine, and you can already see the disconnect she has with kids = good; adults = bad. Promising stuff.
Katherine gets some more development. I already like her fairly well, and we start to dive into her inner doubts and fears. Actually, I almost wish we touched on her doubts and fears more, because that was where the story shined for me. Pitch, too, acts as a sort of foil to Katherine. We see the effects of last volume on him, and it pushes him to some pretty significant lengths.
Also, may I just say that the illustrations are still absolutely glorious? There are black-and-white sketches in these chapter books, which are charming enough, but there are also colored picture books by the author and they too are spectacular! Even if you don't read the book, skim through the pictures!