Okay, this isn't really a five star book, it's more four. I'm giving it 5 because I loved it so much despite some of its more glaring plot holes and minor confusions. 
 Ii gots to say, the characters were a humungous part of why I liked this book so much. 
 The main character Yelena literally made none of them stupid TSTL actions that when we're reading we're like whut? why you do that? which made her a very likeable character. 
 The love interest Valek could be the hottest thing since indoor heating, as long as you aren't bothered by the fact he kills people and is very good at it. Personally I thought that added to his attraction in a really messed up way. 
 Ari and Janco are the best supporting characters EVER invented. I can't tell if its ever suggested they were into each other which would just be fantastic, but they were the most dynamic duo ever. Silent conversations and unflinching loyalty-- these two were adorable. 
 These were only some of the cool characters. 
 The plot moved along at a nice pace and although there were no great surprises that didn't make it boring and it was more because of the actual competence of the main characters. There's a problem? Ooh let's solve it. So simple and yet so satisfying.