Gokusen revolves around the first teaching job of Kumiko Yamaguchi. She is a young, energetic, and determined woman fresh out of college. She manages to snag a job at an all boys highschool where she is unfortunately thrown into class 3-D, the worst behaved, most violent bunch of miscreants at the already rowdy school.Unbeknowst to her students she is not a push over. She is the Granddaugter of the Oedo Clan, a famous and powerful Yakuza group. Though if word were to get out about it Kumiko, or 'Yankumi', as her students call her, would most certainly lose her job.