Idaten tells the real-life story of how Kanakura Shizo, a Japanese Olympic-level marathon runner, and Tabata Masaji, a man who was responsible of setting up Japanese swimming and also was one of the key figures behind the mission to Japan to host its first Olympic Games, with astonishing success.

Both historical and important figures lived in very different periods from each other, but their fight and tenacity are what changed Japan for the better and the world would not be the same after both men's actions and efforts in the name of sports.