Eikichi Onizuka begins his career as a teacher-in-training expecting that he will get a class of attractive, nubile high school girls. When he is assigned the problem "Class O", a group of delinquents and blackmailers, only his tough love is able to win them over.

In the new semester, Onizuka was able to become a teacher at Seirin Gakuen on a sunny day, but the first class he was in charge of was not the high school he admired, but the middle school. Onizuka is disappointed to hear that he is a homeroom teacher for junior high school students, but rumor has it that the class that Onizuka is in charge of, the 4th class in the third grade of junior high school, was a problem class in which there were three homeroom teachers who had quit school due to mental stress.