This book took me a while to get really into (a good hundred pages, if I were to be completely honest) but everything after more than made up for the slow, and somewhat confusing start. I didn't realise this book was a spin-off to begin with, and having never read The Grisha Trilogy, that is probably why it was a slow start for me. I had to pay more attention to world building than anything else to start, but once I understood the setting, I fell in love with the characters. (this next sentence contains a spoiler) Whenever Kaz ripped that man's eyes out, who had stabbed Inej - I'd say that's when I was like "goddamn, I love this character." (spoiler free again) And Kaz really is what made this book for me. It was full of great dialogue, sarcasm, wit, fantastic world building, and truly an impossible heist, as suggested. 5/5 stars, I fell in love with the characters, even Wylan (which annoyed me at first). This is getting a place on my shelf of favorites.