The story focuses on Kenichi Shirahama, an average 16-year-old high school student who has been picked on his whole life. However, on his first day of class, he meets and befriends the mysterious transfer student, Miu Fūrinji. Driven by his desire to become stronger, he follows her to Ryōzanpaku, a dojo housing several masters of diverse martial arts, led by her grandfather Hayato Fūrinji, who is known as the strongest man on Earth. After learning basics from Miu, Kenichi is able to beat a high-ranking member of the school's karate club, and becomes a target for all the delinquents in the school.