At a prestigious school warped by verbal abuse, dehumanization, and academic discrimination, an unnamed narrator has been enduring a miserable existence. This changes when an underclassman, Kurumi Hoshimiya, suddenly reaches out. With dyed highlights hidden beneath her black hair and a mischievous smile, Kurumi forces the narrator to take her hand, drawing them into a two-person resistance movement aimed at tearing down the oppressive school.

The protagonist is a student crushed by the school system, trapped in an environment that prioritizes grades over humanity. Kurumi Hoshimiya is a rebellious and enigmatic figure who acts as the catalyst, dragging the narrator into her schemes. Together, they are the sole members of this resistance. The core conflict is their war against the institution and the adult-run systems that enforce academic discrimination and dehumanization. The story takes place almost entirely within the prestigious school, with a particular focus on an empty clubroom where the two meet after class to plot their acts of defiance.

Their rebellion is not a large-scale revolution but an intimate descent into depravity. The narrative arcs involve their shared plotting of small-scale terrorism against the school, the development of their improper relations, and the abandonment of conventional morality. They exchange kisses, commit sins, and embrace their identities as bad children, following Kurumis recommendations to abandon right and wrong, stop chasing grades, and rebel against the grown-ups.