Season 1

Takahashi Tetsuo, a biology teacher at Shizaki High School, has been fascinated with "demi-humans," beings with characteristics that differ just slightly from humans, since he was in college. He wishes he could have a c…

Machi Kyouko is a dullahan, a demi-human with roots in Irish legend whose head and body are separate, and one of only three of her kind in the whole world. One day, she stays after school to talk to Tetsuo about herself…

Succubi are demi-humans that arouse sexual desire in men and cause them to have obscene dreams. One such succubus, Satou Sakie, is extremely careful in every facet of her life, from where she lives to the trains she rid…

Kusakabe Yuki overhears some girls saying mean things about her. Gossip is not an uncommon problem among high school girls, but Yuki is particularly worried that it's happening because she's a demi. Tetsuo is sympatheti…

Yuki has become a bit more optimistic, thanks to Hikari and Machi. She's learned to trust Tetsuo a bit more since what happened last time, and has decided to tell her what troubles her about her own nature as a snow wom…

Keeping his promise to Himari, Tetsuo visits the Takanashi household to talk to the sisters' parents. Though the twin sisters' names differ by only one letter, Hikari is a vampire, while Himari is an ordinary human. Tho…

As she's walking through the school building, Sakie spots a beautiful blond-haired boy sitting on the floor, crying and hugging his knees. He says his name is Kurtz and doesn't seem to be a student of Shibasaki High, be…

The midterm exam score rankings are posted. While Himari and Kyouko earned high ranks, Hikari is scolded by Tetsuo for getting three failing grades, so she resolves herself to study along with Yuki. Meanwhile, Yuki drop…

Sakie the succubus is spending her evening at home alone, ranting her troubles to her teddy bear, when she receives a call from Ugaki. Sakie knows she can't avoid the influence of her inborn aphrodisiac effect on romant…

Dullahans are demi-humans whose heads are separate from their bodies. Naturally, Tetsuo is intrigued by the unique traits of dullahans, but Kyouko is just as interested in learning more about her own body. Tetsuo has th…

Tetsuo has offered to work with the girls to figure out how Hikari and Yuki, who don't handle heat or sunlight well, can spend summer in comfort. But the school's head teacher suggests that the demi girls' total relianc…

Summer is finally here! Hikari pays another visit to the biology prep room to cool down, and while she's there, she asks Tetsuo for permission to reserve the school pool for a day. Ignoring Tetsuo's concerns that a vamp…