One detail that struck me as part of the horror elements of the book but slightly disjointed from the main plot is the other supernatural bits. Adelaide talks to her dead mom, and there's the ghosts in the neighboring town that she visits with Fiona. These spooky elements are just accepted parts of the world, and feel like flavor, but in the end don't add much to plot or world building . (This feels especially the case after reading City of Bones, where the ghosts feel like a flavor element at first but there's a later reveal where they get explained satisfyingly by the plot.)

Related to the detail that the truth of the steamer trunk being Elizabeth, Adelaide's sister, I think the rest of the plot around Elizabeth and her kind is shaky. There's Francisco and Carlota in a cabin near her who call Elizabeth a goddess in one brief scene from Elizabeth's point of view; however, despite Adelaide meeting them at the climax of the book, they are never mentioned again after this encounter. Additionally, we find out that the Reeds have had a child like Elizabeth but they killed her, and I wish I had had a little bit more foreshadowing around this before the final moments of the plot.

It's hard to say why this setup was unsatisfying to me, but I kind of wished there was either more or less detail. Having Elizabeth be unique and otherwise unexplained with no other details would have felt more metaphorical; alternatively, knowing more info about why this is happening in the world and to learn how she fit into it would have also been more conclusive. This middle ground just felt a little bit too loose for me.

Finally, minorly, I did appreciate the Sam trans reveal later in the book. It wasn't clear to me why Grace was shunned as a teacher. I bought into the misdirect that Sam was just a "strange" kid (to others, mostly around hyperfocus and lack of filter) and it was this behavior that Mrs. Reed was so concerned with fixing.