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.
I can judge a student's health 
with one look at her face.
Puedo juzgar su salud con verle la cara.
Puedo juzgar su salud
con verle la cara.
Noto de cara a condição de qualquer aluno.
Я сразу пойму по лицу ученицы,
если с ней что-то не так.