The Imperial Seal, handed down since ancient times, gives great power to the warriors it selects. Rikuson's family once guarded the seal until Sonsaku stole it. Urged on by his mentor, the reluctant Rikuson joins Sonsaku's side, hoping to learn what the seal truly wants. Before he can, assassins kill Sonsaku and the seal is lost. Set in an age of civil war, when vast armies meet in huge battles and ordinary people fear the sword, this adventure series follows Rikuson as he sets out to find the seal again and learn his own destiny.