Flawed (Cecelia Ahern)

"If you break the rules, you will be punished. Celestine North lives a perfect life. She's a model daughter and sister and she's well-liked by her classmates and teachers. She's also a girl of logic. To Celestine, every problem has a solution. Every action is either right, or wrong. Celestine has always known about the Flawed, second-class citizens who are branded as punishment for their crimes. And she always thought they must deserve their punishment....