Due to family troubles, Ren Uesugi and his sister, Mihato, leave their home. They end up moving to the city but find themselves with a lack of money. Somehow they are able to find work in the form of the Kuonji family's mansion, being employed as servants to the three sisters of the Kuonji family: Shinra, Miyu, and Yume. Being a servant also associates Ren with the mansion's additional servants and the Kuonji sisters' friends.
Due to poor grades, Tsukune Aono, an average high school student, has been unable to get accepted into any private academy of his choice. By exceptional accident, the only school to accept him turns out to be anything but ordinary; the school is attended by youkai disguised as humans. Fearing for his life, he attempts to escape only to meet Moka Akashiya, a beautiful girl who just happens to be a vampire. Despite this, Tsukune decides to stay at the academy, hiding his human nature from students and teachers. Tsukune also discovers that when the rosary around Moka's neck is removed, her true nature emerges.
Shungo is a normal high school student living in a huge house. One day, his sister Ryoko sends Mayu and Mikihiro Tsukimura, two siblings, to live with him to help Mayu overcome androphobia (fear of men). Unfortunately this is acomplished by making Mayu and Shungo share the same room, bed, and even baths together. Making things even worse, Reika Hojo, the student-council chair, ends up becoming their maid due to a video shot of her which Ryoko takes while Reika tries to seduce Shugo as a blackmail.
Sana Hikada returns to his hometown after 5 years away living in Tokyo. Although there are some changes to the town, most has remained the same. On a detour to his apartments, he notices a girl in a shrine maiden outfit watching him when he visits the shrine. He finds out, the next day at school, that this girl is actually Nanaka Yatsushiro, his old childhood friend whom he gave a bracelet to before he left, that she still wears, even to this day.