Saburo is a high school student who excels at sports but not so much at his studies. One day, he is transported back in time—more specifically, to the Sengoku period in the year 1549. There, Saburo meets Nobunaga Oda, his doppelgänger from half a millennium earlier. Nobunaga is the son of a magistrate in Owari Province and is in very poor health, which is why he asks Saburo to take his place in the effort to unify Japan.