Avery and her friends, now hidden in the secret tunnels under the castle, continue to uncover secrets and thwart plots, some of which they started. And the question always comes back to this: Who is the king's heir? They discovered the king's son, but the portrait of the queen after her birth showed twins. Is it possible there is a daughter ... Avery? Kate?

The Paper Boat is the intriguing conclusion to the Thirteen Series. It is first and foremost a mystery. It is short and easy to read, fitting the middlegrade age group. As in the previous books, the story moves quickly from one situation to the next, the characters barely blinking in adjustment. The quickness wasn't something I liked, but it worked well for the story.

The question is asked: Is it actually good to be a princess? There are constant plots to dethrone and kill the king, queen, and the royal children. Who wants to live that way, always looking over one's back and not trusting anyone? Sure, the luxury is great, but there is a lot of responsibility accompanying it. Some of the responsibility can be used to help others, a possible redeeming factor. But if given a choice to be a princess or an ordinary girl in a loving family, what is the best decision?

The story also explores what it means to be family. What if your parents aren't actually your birth parents? Can a group of friends be family too? These and other questions are touched on through the experiences and actions of the characters.

I enjoyed this book and recommend it as an appropriate, Christian, middlegrade fantasy.

I received a complementary copy of this book. All opinions are my own.