The First Book in an Action Packed Duology

I've already read this book and I absolutely love Marie Lu's work. I already preordered the second book in the duology and can't wait for it to come out in a little over a month. The story is so unique and the characters have such unique personalities that draw you to them right away. I love how this book started off being so action-packed and causing you to become emotionally involved right away. I can't wait to read this book again before the next one comes out and then I can't wait to read that one to finish off this compelling story.