The film is adapted from the popular Japanese novel Renxia series. The loyal gangster Akimoto accidentally took over a high school that was on the verge of bankruptcy due to poor management. They are gangsters, but they serve the society, help the weak, value feelings and loyalty, have a high sense of responsibility, and resolutely reject injustice. The gang leader Himura Seiji has made every effort to contribute to society. Himura looks vicious on the surface, but his inner enthusiasm and sense of justice are quickly recognized by the teachers and students of the school. Everything seems to be going well, but the gang members suddenly find that someone with bad intentions wants to take over the school. The old-school gangsters protect the school in their own unique way, influencing the problem students and parents, as well as the teachers of the school.