It's the Warring States period. Many a warrior dream of unifying Japan. Toyotomi Hideyoshi, on the verge of realizing that dream, takes a massive army led by Ishida Mitsunari to surround Odawara Castle, currently being defended by Hojo Ujiyasu.

The death of Hideyoshi Toyotomi, ruler of Japan, plunges the world into turmoil yet again. Mitsunari Ishida tries to protect the Toyotomi clan by opposing Tokugawa, the strongest faction, but his behavior only causes misunderstandings and further isolates him.

Having learned of Mitsunari Ishida's taking up arms, Ieyasu Tokugawa decides to march his massive army to take him on at Sekigahara. Nobuyuki Sanada, who had parted with his brother Yukimura in the lead-up to this event, would have to join the fray as part of a unit separate from Ieyasu's, and under the control of his son Hidetada.

While the Sanada brothers Nobuyuki and Yukimura face off at Ueda Castle, and Kagekatsu Uesugi and Kanetsugu Naoe take on Masamune Date and Kojuro Katakura at Aizu, the curtain is drawn on the Battle of Sekigahara. With the overwhelming numerical advantage created by Yukimura's stalling of Hidetada's forces and a formation that fully utilized his geographical superiority, Mitsunari takes the upper hand in the early going.

Mitsunari Ishida was killed in the Battle of Sekigahara. Following the war, a meeting is held at Edo Castle to determine the fates of those that had stood against the Tokugawa clan. Yukimura Sanada's sentence, in particular, attracts heated debate from all those present. Amidst all the voices baying for his blood, not least Hidetada Tokugawa, who had fallen in battle to Yukimura, and was late in reaching Sekigahara as a result, Ieyasu Tokugawa asks Yukimura's brother, Nobuyuki, for his thoughts.