Princesses aren't all they are made out to be. As they grow up, they can be just like anyone else. Snobbish, quiet, normal. As they grow in years, it is a trainers duty to whip them into shape so they can rule their kingdom when their parents are gone. That is your job. You are a member of the Society of Princess Trainers.
In the Kingdom of Versaille, 18 years ago, 4 Princesses were born from the queen herself. Having this many daughters must have been a miracle, a problematic miracle. 18 years have passed, and each of these girls are to compete for the throne as the king has fallen ill. The only problem, they haven't a clue how to be what their status says. A princess. Knowing this, the Queen called on the only group of people that can help them out. The SoPT.
