Gorō Ōishi is a cheerful junior high school student known for his strong sense of justice and hot-blooded nature. He is introduced when he transfers into a new school, Aozora Gakuen, where his life quickly becomes eventful. As a superb athlete, Gorō possesses considerable physical talent, but his most defining trait is his short temper and bellicose demeanor. When his anger reaches its absolute limit, he unleashes his signature ability by shouting Bakuhatsu da! (I am going to explode!), which triggers a transformation that makes him amazingly strong. This explosive power becomes the primary tool he uses to overcome various challenges and help those in need at his school.

Soon after arriving at Aozora Gakuen, Gorō demonstrates his athletic prowess by stepping in as a substitute for members of various sports clubs, quickly making a name for himself as a school celebrity. It is Mayumi Saegusa, the intelligent, strong-minded, and kind leader of the school newspaper club, who takes a particular interest in him. Concerned for Gorō, she invites him to join her club, and he accepts. In the newspaper club, Gorō teams up with Ippei Wajima, a timid yet cheerful and kind boy who serves as the club's photographer. Together, this trio dedicates themselves to solving the various problems and incidents that arise within the school.

Gorō is motivated by a deep-seated desire for everyone at Aozora Gakuen to enjoy their youth in a great school environment. His role in the story is fundamentally that of a problem-solver and defender of his community. Rather than fighting external villains, his conflicts are rooted in the everyday disputes of school life, using his unique brand of explosive strength to help his peers and ensure a positive atmosphere for all. His key relationships are central to this mission. Mayumi acts as his concerned and intelligent ally, providing guidance, while Ippei is his reliable and kind-hearted partner on the front lines of their investigations. Through his work with the newspaper club, Gorō experiences a degree of development, channeling his raw, explosive anger and athletic abilities into collaborative efforts to resolve school incidents, moving from a lone substitute athlete to a key member of a team dedicated to the welfare of the student body. His notable ability, triggered by his explosive shout, grants him the incredible physical strength needed to subdue conflicts and overcome obstacles that standard athleticism cannot handle.