Trailer: Haru ni Chiru by Takahisa Zeze

Jinichi Hirooka is a former boxer. He lost a boxing match by an unfair decision and he then moved to the United States. After 40 years, he returns to Japan and happens to meet Shougo Kuroki in a bar. Shougo is a boxer, who is going through a hard time, because he also lost a mach due to an unfair decision. Soon, Shougo gets knocked down by Jinichi for the first time in his life. He then practically begs Jinichi to coach him in boxing. Jinichi accepts his offer and they eventually work together to win a world championship belt.