I enjoyed this book, but for the sake of not giving any hints about a mystery book in my review, sadly, we are only gonna talk about the things I didn't like in this book.
These characters are for the most part bad people and you really aren't sure who to trust at different times which makes the mystery element powerful. That being said, I think the pacing of the mystery unraveling was off at times. More often than not it was too slow, we see the character have some sort of revelation but in my opinion it takes too long for the reader to get the information that allows the reader to follow the thought process of the character. My other gripe is that the island's magic didn't always make sense like the omens and patterns did not click for me. 

I did not enjoy the jump at the end from gun to head going to die straight to happy with kids in the city. Could've used another chapter there, I want to know what the fallout on the island looked like. Genuinely felt like pages of the book were missing