Tells the story of students, parents, and teachers. In a society where teachers' rights have fallen due to students who cross the line, parents who don't know the line, and teachers who draw the line, the drama introduces adults who are not afraid of children and tries to properly teach children what they did wrong. Na Hwa Jin is a field supervisor at the Teachers' Rights Protection Agency. He is a hexagonal person with perfect mentality, physicality, and brains, and is the designer of all the plans for the Teachers' Rights Protection Agency. He is also called the 'Grim Reaper' because he is not afraid of absurdity, fear, or compromise, but he is a character who struggles to protect justice and peace.