So Si-min used to be a professional boxer, but because her father was in debt, she had to choose to fight fake matches to obtain high funds. Seven years later, in order to make a living, she chose to work as a contract teacher in a school. After arriving at school, she discovered that bullying was very common on campus. One of her students was a victim of bullying. With an innate sense of justice, she decided to personally punish these evil students in order to free her students from the shadow of bullying.
The main character of the bullying team is Han Su-gang, a boy born in a chaebol family. His parents divorced when he was a child. He lacked love since he was a child and used violence to gain happiness. In addition, he is also a very good boxer, so he does all kinds of evil in school, and no opponent can even beat him. In addition, teachers at the school chose to ignore his bullying behavior due to his family background.
But So Si-min is not afraid of him. When she sees Han Su-gang bullying students again, she puts on a cat mask and uses violence to solve the bullying! The scene of her beating Han Su-gang was recorded and spread to the Internet. This also led to her true identity under the mask being discovered by Han Su-gang. Therefore, Han Su-gang took the initiative to set up an arena to celebrate the anniversary and challenge So Si-min. Who will win this game?