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 chance to talk with one, but since the demi-human population is fairly low, he's never even met one. But then the school gains a new math teacher, Satou Sakie... who happens to be a succubus.
Stories say people you drink 
from become vampires
تقول القصص أنّ من تشربون الدّماء 
منهم يصبحون مصّاصي دماء
Das Opfer eines Vampirs soll
laut einem Ammenmärchen
Dicen que la gente a la que muerden
se vuelven vampiros
Dicen que la gente a la que mordéis
se vuelven vampiros
On dit que quiconque est mordu
devient aussi vampire,
Secondo la leggenda,
chi viene morso da un vampiro
A lenda diz que quem 
é mordido vira vampiro,
В легендах говорится,
что укушенный вампиром