Among the people of the grass-covered plains of the country Sairou, Wakaosa Soruen of the Baku tribe lives each day among the wind and the horses. One evening, his father Tauru goes to the country Hokkan to take the crown prince Rimudo away. Although Soruen wants to welcome in this young boy, for some reasons Rimudo is unwilling to accept him. One day Soruen is forced to become Rimudo's mentor as they embark on a dangerous and harsh journey. This is the story of the deep bond that forms between them.