I KNEW it!!! That's all I have to say about the ending of this book. In a good way. It's one of those endings that has you saying "No way!" while at the same time you were secretly hoping for it to happen the whole time.This second book in the series started off slow for me. In terms of plot, things move a little slowly in the first half while we find out what happened to Lena in the time after she escapes Portland. We learn more about the "Invalids" and how they live. There is more world-building. All of this is interesting and necessary but the book really gets going in the second half which has a lot more action.In terms of character, we see a lot of Lena's progression from soft, sheltered, whiny girl to hard, competant, strong and smart. She still has an emotional vulnerability that draws the reader in without being too angsty. I loved Julian! It was refreshing for me to see a male character who is vulnerable and emotional while still remaining masculine. He really became a favorite of mine. I started off thinking I was going to rate this about a 3 but after finishing I give this a solid 4 stars. I'm very much looking forward to the third book in the trilogy!