In a world where vampires and humans coexist, there are two royals, from two different realm. One was a girl, and she was a vampire, but no one knew that and she wanted to keep it a secret, since vampires where hated. The other one was a boy, a human, named Nishimura Riki. One day, a dance was thrown at the princess's castle. A lot of princes and princesses were invited and Nishimura Riki was one of them. They both didn't know each other, but the dance gave them the occasion.