- The internal conversations. The internal conversations between Eva and Addie are written in a different font between <> symbols. This was so subtle and clever, and really improved readability and clarity. As I was reading The Pledge actually I thought the entire time that font changes would be a really easy way to differentiate between languages. I'm glad someone else had the same idea!
- The premise. While I will admit the book did have a very Dr. Jekyll and Mr. Hyde kind of feel to it, with the huge amount of dystopian and post-apocalyptic YA books coming out recently, this was one of the freshest and most unique books in that genre that I have read in a while.
- The parents. Eva and Addie's parents' reactions throughout the entire book felt so honest and realistic. They just want both their children to be healthy, and they want to trust the doctors trying to help their family. Zhang could have easily been painted the parents as villains or had them immediately jump to Eva and Addie's aid, but that wouldn't have been nearly as heartbreaking as some of the decisions they made in this book.
- The conspiracy. The over-arching conspiracy in the book was very well constructed and felt realistic given the conditions Eva and Addie are living in.
- The suspense. I could not put this book down. The pace, action, and suspense are non-stop and I didn't feel there was one dull or unnecessary moment throughout the entire story.
This was one of the most unique YA dystopian fiction books I have read in a while. Not only that, but the story is so suspenseful that it was almost painful when something came up and I had to put the book down.