Cross Academy is a place of learning and refuge between humans and vampires who live amongst together. But the vampires are kept a secret between the day class students. The guardians Yuki Cross and Zero Kiryu, the adoptive son and daughter of Kain Cross, the founder of Cross Academy. Watch over the day class and the night class students to protect them they must keep them a secret. But then, there's a new student of Cross Academy, will she be accepted as one with the day class or one with the night class? Or will she be put as another guardian for the headmaster of Cross Academy?