Jin-su, a 9-year-old elementary school student whose dream is to become a boxing referee, doesn't know why he wants to be a boxing referee, but at some point he started to feel a sense of duty to become one. However, he is suspicious of his father, who has nothing to do with boxing. "Where did the hot boxing referee's blood flowing in my body come from?" Jin-su turns his gaze to the three uncles who used to be around his mother. Seong-jin, Bi-chan, and Wang-gu. They are all uncles who only look at their mother and exercise at the boxing gym that their grandfather used to run. Jin-su sees from these uncles the qualities that a boxing referee must have and learns the whole story. On the day his mother announced her marriage to the three people, everything happened because of that.