10 kingdoms were at war with each other. The war lasted 100 years, it had gotten to the point that no one even knew why the war originally started. Soon, the rulers of the kingdom have all decided to come to an agreement with each other that ended the war. They knew that they had to make their children get along with each other so they never had to fight a war again. So they decided to make a school where all the royal children from 13 to 18 met each other. However, each royal family forgot to mention that some of their kids are yanderes~