Bureaucrat Takashi Mikami takes over Class 3-2 and asks the 29 students a single question that provokes curiosity, conflict, and unexpected change.

Kanzaki investigates a murder linked to his old exposé; Mikami provokes student debate; ministry plots and dark connections begin to surface.

Mikami meets the murderer, Yuzuru; Kanzaki searches for the truth; Mikami's past resurfaces with the arrival of a mysterious young man.

As Saejima's link to the murder is exposed to the public, Kanzaki struggles with guilt; students debate as cryptic faxes from Yamato Takeru stir tension.

Kanzaki and Mikami meet Yuzuru and discover her tragic past; the class take part in a rigged business contest, defying authority with bold ideas.

A tabloid exposes Mikami's brother, Kota. Pressured by students, Mikami finally breaks his silence with the help of a colleague and Kota's ghost.