Matsugorō Ogami is a high school student whose formidable size and peerless skill in combat have secured his standing as the area's most feared delinquent. His long list of rivals and followers know him by the moniker "Praying Matsugoro," a name earned from his habit of offering a prayer for those he defeats. His existence is defined by conflict until a compulsory volunteer post places him at a local kindergarten. There, he encounters Nagasaki Koume, a young woman with a profound opposition to violence. This meeting profoundly alters his course. Driven by his affection for Koume and a need to shield the kindergarten from a group of menacing yakuza, he strives to reform his ways, even directing his gang to perform repairs and other peaceful tasks.

Yet, the yakuza's relentless threats eventually compel a return to the violent methods he has always relied upon. He confronts and overpowers the criminals, saving the kindergarten but violating Koume's core beliefs, as she condemns his brutality despite the result. His story includes an arm wrestling match in a ramen shop and a school festival dance. His conflicts also involve a rollerblading girl gang; after he disarms its leader, Kyoko, who sought vengeance for her brother's injury, and remarks that women belong in kitchens, her hatred transforms into infatuation. The narrative culminates when the yakuza abduct Koume, forcing Matsugorō and his allies to mount a rescue operation.