Grishas have powers like healing and controlling tides and fire, but their home Ravka has lost most of the war against Fjerda, a country that kills them for having these powers. They consider them unnatural and dangerous, and some of them burn them in a pyre. Now it seems there is a drug that a scientist has developed that can amplify their powers immensely but is also so addictive that most people that try it die while trying to get more. 
 In a small island called Kerch, Kaz is the second in command of a gang. He's considered a demon, feared by most and a target of the other gangs. But when a man offers him 30 million to rescue the scientist that has the formula for the drug, he decides the risk is worth it, so he can get the money to finally have his revenge on his brother's murderer. He designs a plan to infiltrate Fjerda, and gathers a team: Inej, a young girl that he saved from a pleasure mansion in exchange for her working as her spy and assassin. Jesper, a shooter that has a serious gambling problem. Wylan, a young boy that can make bombs and whose also the son of the man that hired them. Nina, a Grisha that can heal people but also kill them. And Matthias, a Fjerdan that has a history with Nina. 
 I loved this book!! Its slow paced at times, but its interesting and you just want to keep reading. I LOVED the characters, especially Inej and Kaz. I know the book is a bit predictable, but the characters are just too endearing and the plot grabs you. 
 Inej is amazing. She's strong and smart, quiet and loyal. She has such a hard past. She is so grateful to Kaz for saving her, and treating her like she's free and not owned, and eventually, realizes she's in love with him against her better judgment. Being a slave and sold as a prostitute was so hard, that it breaks my heart. While the book doesn't give you any horrible details, you can tell how much she suffered by the way she panics just looking at anything related to that place. I also love that she refuses Kaz, knowing that his phobia is so strong that they won't be able to have a real relationship. 
 I also love Kaz. He's so broken he's made this whole persona whose only purpose is revenge. His phobia is the only remanent of weakness and it's his body's way of dealing with his pain. He doesn't allow himself to grieve or feel anything but hatred, and while it drives him, it's also hurting him. It seems that Inej is the only thing that makes him feel something else, and in a way her being taken drives him even more than his need for revenge for the death of his brother. 
 Jesper was so much fun. He brings some deserved comedy to the book, but he's also faulted and broken in a way. His need for adrenaline and his gambling can make him do stupid things, but in a way that makes the character great. I thought he had a crush on Inej at first, but then realized it was on Kaz. It seems he's falling for Wylan, and while sometimes a relationship like that can be a little forced, it felt natural and exciting to see develop. I wasn't expecting him to be the one that sold them out, but he didn't mean to compromise the mission. He can be naive and blind because of his fear for his father's farm, but he can't stop himself at the gambling tables. I hope he grows as a character. 
 I loved Nina and Matthias. Nina is so strong and smart, and Matthias is the type that has a really strong sense of moral and duty to his country and religion, so strong that he's blind to the radical ways of his people and has a hard time opening his eyes to the lies. It is only with Nina that he starts to doubt his beliefs. Matthias reminded me of Wakka from Final Fantasy X, he's the typical fervent believer that thinks his war and murders are justified. When he feels attracted to Nina and starts to see her as a human, bold and brave and compassionate, he's conflicted with himself. I love how Nina is totally in love with him, but at the same time is strong in her beliefs and won't put her country in danger at any cost. 
 I wasn't expecting Wylam's father to be the bad guy, but I also wasn't expecting Kaz to use Wylan as Kuwei. 
 I can't wait to read the next book. I hope we get to see Ravka, meet more Grishas and expand the world even more. It's such an interesting universe that I want to explore the whole map. And I really hope they get the recenge they deserve.