Ken Komatsubara, a fifth-grade boy, transfers to an elementary school in the upscale Ginza district of Tokyo. Without explanation, the Ministry of Foreign Affairs issues a Caution Advisory for him, marking his presence as a significant event that immediately draws attention from multiple quarters. As Ken navigates his new school life, his arrival sends shockwaves through the local police, entrenched neighborhood gangsters, and even overseas private military companies. In a town known for its luxury brand shops, the fighting abilities of a boy seemingly born from violence are unleashed, disrupting the fragile peace of the district.

The story follows Ken as he becomes the focal point of a growing conflict between these rival factions, each trying to understand his origins and either control or eliminate him. The narrative unfolds across three volumes, beginning with Ken's arrival and the initial ripple effects of his presence. The middle arc delves into the reasons behind the government's advisory and the nature of Ken's abilities, escalating tensions between the police, yakuza, and mercenary forces. The final arc resolves the conflicts as the various forces converge on Ginza, leading to a confrontation that determines Ken's fate and the future of the territory he inadvertently stepped into.