Newly graduated Yamaguchi Kumiko is an idealistic teacher who entered Shirokin High to become a math teacher. With high hopes for her students, her world is turned upside down when she discovers that she’ll be teaching class 3-D, the most challenging class to manage. Class 3-D is filled with students who resemble delinquents and troublemakers. The students show no respect for teachers and little kindness. Each student dislikes teachers, as almost everyone has no good memories of them. The class leader is Sawada Shin, who is well-respected due to rumors that he beat a teacher to death. The students try their hardest to bully and mock her to make her quit, but all their efforts go to waste because Yamaguchi is not an ordinary teacher. Yamaguchi Kumiko is actually the fourth-generation heir to the Oedo group, a yakuza clan. Even though everyone in her clan wants her to be the next leader, she has made up her mind, and everyone has accepted it.
