Set in Kansai Fifth Technical High School, renowned for its unruly students, especially in Osaka, Osu!! Karate Bu unfolds within its infamous karate club, feared as the toughest in the area. When newcomer Matsushita Tadashi enrolls to fend off bullies, he finds himself entangled in unexpected challenges. The narrative pivots to the club's leader, Takagi Yoshiyuki, Osaka's most formidable thug, as he battles to safeguard both the karate club and the city itself.