Cady turned sixteen. She is sure that at least two very important things will happen soon. First, she will have a boyfriend. Secondly, some other significant event will happen in her life. Cady has been friends with Rosie for so long that it seemed that nothing could separate the friends. But with the start of the school year, a crack appeared in their strong friendship. By the way, this is not even a crack, but a real hole called Susan. She's new at school. Susan is beautiful, smart and extremely popular. And, it seems, she decided to take Cady’s place and become Rosie’s best friend.