赵强子（金喜善 饰）曾经是人见人怕称霸一方的不良少女，如今，早已经“金盆洗手”的她藏起了所有锋芒，成为了一名母亲。让赵强子没有想到的是，自己的女儿吴雅兰（金裕贞 饰）竟然成为了校园暴力的受害者，更让赵强子难过的是，当她鼓动女儿为自己讨回公道时，女儿竟然选择了沉默。从来不按常理出牌的赵强子想出了一计，就这样，她入驻了女儿的班级，成为了女儿的同班同学。 充满了冲突的校园生活就此拉开序幕，想要解决问题的赵强子自己却成为了最大的问题。在这里，赵强子需要面对的不仅仅是来自学生们的非议和压力，更在无意之中发现了学校财团那不可告人的秘密。
This drama is about Jo Gang-ja, a mother who was known as a tough girl in high school. Her daughter Ah-ran is bullied at school and when Gang-ja finds out, she makes it her responsibility to stop her daughter's bullying. She ends up becoming a high school student again.
