High school biology teacher Tetsuo Takahashi may look like your average everyday instructor, but beneath his gentle appearance lies something less ordinary: his fascination for the "Ajin," more commonly known as "Demi." Although these half-human, half-monster beings have integrated into human society, Takahashi believes that much about them will remain unknown unless he interacts with them firsthand. Demi-chan wa Kataritai follows Takahashi's daily life in Shibasaki High School together with his three Demi students—Hikari Takanashi, an energetic vampire; Kyouko Machi, a gentle dullahan; and Yuki Kusakabe, the shy snow woman. Along the way, Takahashi also meets fellow teacher Sakie Satou, a succubus with an aversion towards men. To fulfill his goal of learning more about the Demi, Takahash