Jōji Aki, a former yakuza member turned licensed teacher, is compelled by his superior, "Kashira," to instruct at a high school overrun by delinquents. His underworld past shapes his unorthodox methods, resolving clashes through physical prowess honed in organized crime. Entangled in a personal feud with a fated rival, he also grapples with burgeoning feelings for a colleague, straining his professional focus.

Prone to impulsivity and bound by yakuza principles, his instincts frequently conflict with pedagogical expectations. The narrative chronicles his turbulent journey to reconcile these dual lives—battling classroom chaos while confronting remnants of his criminal history. Central to his arc is the push-pull between violent legacy and the disciplined ethos of mentorship, as he navigates a precarious path toward self-redefinition.