That's exactly what I needed to read. And I think I read the book way too fast, but I just couldn't put it down. 
 I love the story, the whole idea is great. Ivy is a pretty strong character, (she reminds me of Tris Prior in some way, especially at the end: I wanted to scream at her to not do this). I like a character who can fight for what is right even though you wish they wouldn't (her dad and sister definitely didn't deserve her love and her sacrifice, but she was too nice and kind to see it). And Bishop is an incredibly cute, sweet but strong character. 
 Basically, I loved the story, I loved the main characters, and now I'm going to pick up the next book.