So, this is a really clever heist. And moderately engaging book. I still feel like Hale is an underdeveloped character.
But my main thing is that all the characters act like they're in their twenties. And I get it’s YA (young YA for sure) so the characters are going to be teens. But then they should act like teens. Kat is nothing like a fifteen year old. And it’s like Carter knows that because she keeps telling us that Kat is fifteen because clearly we’ve forgotten it as she and Hale jet around the world. And her relationship with Hale (even with his lack of development) is way too emotionally mature.
So one way or another you have to suspend a whole lot of disbelief. Either buy into the story that a fifteen year old acts like this. Or ignore it every time it says Kay is fifteen and read it like she’s 22. I prefer the latter.