The Voyage of the Dawn Treader is the fourth book in the "Narnia" series. It was written by C.S. Lewis. Other books in this series are The Magician's Nephew, The Lion the Witch and the Wardrobe, Prince Caspian, and more.
It is about Edmund, Lucy, and their bratty cousin Eustace. They were sucked into Narnia where they see Price Caspian (now the King.) Eustace in the adventure learns important lessons while Edmund and Caspian learn what greed can do to you.
As I said on the title I am focusing the book and movie unlike usual. The book (in my personal opinion) was the least exciting, the least adventurist of all the books in the Narnia series. Don't get me wrong I think that it is a worth read and watch. Though I would say I felt less intrigued to read more and more. Though you may have a different opinion.
The movie in relation to the book was OK. I think the makers of the movies noticed it needed some tweaking to hold the watcher's attention. Thus the movie did NOT follow the book. I think the movie still was fairly good.
I would say it is very appropriate for Christian teens.