Sixth-grader Chang is a sensible child. His parents have been working out of town for years and he started living with his grandparents since first grade. He is quite helpful with housework and has a pleasant personality. One day, he happens to witnesses his grandfather, who works as a building guard, submit to the humiliation of a resident. Chang is shocked and, without realizing the impact of this incident on his own mind, subsequently takes the initiative to make an unusual new friend.