Though the majority of the book feels like your standard fetch quest, it really shines in the last 1/3 with an engaging climax and an ending that probably isn't what a reader wants, but what they need. It really made reading the book worthwhile and I'm glad to see more of these kinds of endings.

Also kudos for the great 1920s Mexican setting along with the use of Mayan mythology, which I see so rarely when it comes to mythic stories.