In 17th-century Japan, the ruling Tokugawa shogun is dead, and one of his children must now inherit the throne. Though this honor should go to the troubled eldest son, Iemitsu (Matsukata Hiroki), most of the nobility seems to favor his younger brother, Tadanaga (Teruhiko Saigô). This leads to an intense rivalry between the siblings that only intensifies when it is learned that Iemitsu's cohort, the brilliant swordsman Yagyu Jubei (Sonny Chiba), was responsible for the shogun's death.