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.