Has your tween girl watched the Disney movie Descendants? It's about a group kids whose parents were all of the evil people in fairy tales like Maleficent. They were all taken to an Island and locked there under a protective spell to keep them there forever. The upcoming Prince charming though thinks that it's not fair for the kids, who are innocent, to be punished for their parents evil deeds so he invites a group to where all of the kids from the heroes and heroines in the same stories live. It's Disney so it's a feel-good story.
The book however is much different. I haven't read the book, but my daughter, after seeing that the movie was based off a book, decided to read the book. She says that the book is completely different than the movie. She even stated that she can't even see how the movie came from the book and that tells ya how different it is! She did say the book was okay. I asked her, if she had not seen the movie, then would the book be a good book. She said sure (without much gusto). She said the book wasn't too exciting.
So there ya have it! Maybe in this case, the movie is better than the book!!