I agree with your rating, I also gave it a 4 out of 5. Some of the plot points did not wrap up as satisfyingly as I would have liked, but TJ Klune has a knack for writing sweet characters and I was really rooting for them. And it was funny, too! The opening with Wallace had me laughing.

I didn't like it as much as The House in the Cerulean Sea, but it was still overall a good book!