I hardly find anime in which I enjoy this much.
Story is about 4 princes of Grannzreich kingdom who are in need of a tutor for their grooming to be a future king. They happend to reject all previous tutor, so king had to call, Heine Wittgenstein. All of them have different personalities with which Heine has to deal with in order to teach them well.
Story is very sweet and it has a lot of lessons that are even useful for us as readers, not only for princes.
Characters development is great and afer every lesson they princes change their behavior and way of thinking.
Each character has flaws and virtues and they are very easy to like. 4 princes are very different from each other and have never been out of palace. They have no image of how people live. I personaly like the most how they personalites develop during time and how they actions reflect that.
King is also very interesting character and Heine brings a lot of myster in beginning.
I'm right now on chapter 59 and after every chapter I don't get cold. I can't wait for new story and I can't wait for some misterjes to be resolved.
Overall I really love this manga. I wish that there is more useful mangas out there and those with this good character development. They usualy have one personality and stick to it.