Newly graduated Kumiko Yamaguchi wants to make her mark on the Japanese educational system as a teacher. All well and good until she finds out that the class she'll be in charge of is full of troublemakers and rabble-rousers. But those guys don't frighten her though for she has a secret of her own-she's a fourth generation crime syndicate member and next in line to head it up. She's gone straight and wants to be a teacher though, but she's one person in whose class you don't want to be caught fooling around!

 带着一副眼镜，梳着辫子，穿着运动服，看起来有点呆呆的女教师，不管发生什么事情却丝毫不为所动。因为她是呼风唤雨、无所不能的任侠集团「大江户一家」的大小姐。凭着一份正义感和拳脚功夫，痛快地解决学生们的事件。

「白金学院高等学校」倒闭后，失去工作的热忱教师山口久美子，偶然机会被派到有名的「黑银学院高等学院」当教师。又能重新回到教坛的久美子兴高彩烈地上班，然而担任的3年D班又是一个不良少年聚集的问题班级，而且以前经常对立的猿渡也在黑银学院当起了教导主任…。

面对什么事情都不敢兴趣、得过且过的学生们，久美子为了让学生们珍惜人生只有一次的高中生活，与学生们正面迎战！离毕业只有三个月，久美子和学生们的热情而难忘的时间拉开了帷幕。

始终不变的「极道鲜师」的主题，即「友情」「家人」「信赖」「关心」，虽简单而易忘记，却又是珍贵的东西。这次久美子以亲身经历教会学生们许多事情。

久美子回来了！