Synopsis

Yoshizawa Tsuneo (Tanaka Kei), a mathematics teacher at a famous private high school, is always with a smile. His motto in life is “Happiness comes with a smile”. He applied to be the form teacher of Class 3D, a class of students (Takahashi Fumiya, Kubota Sayu, Morita Kokoro, Takahashi Nao) with outstanding academic results. However, every teacher who became the form teacher quit in a short time. In fact, the students in this class entertain themselves by cornering and breaking adults like a game. Yoshizawa answers with a smile even when students have malicious comments or questions. He also wears a grin even after being physically attacked and injured by them. Yoshizawa somehow has a good knowledge of their private information and teaches them with a smile. Their actions keep escalating and they finally plot to kill him. Why did Yoshizawa appear in this school?