The year is 1458. A child is born in the village of Otsuka, in Musashi Province. His name is Shino Inuzuka. After coming of age, he is entrusted with a legendary sword, the Murasame, by his father Bansaku. Shino's father, however, commits hara-kiri after losing face when his brother-in-law, Hikiroku Otsuka, tries to trick him into giving up the sword, Then Shino, devastated by his father's death, somehow comes into possession of a small bead, On this strange bead, the Chinese character ""KO"", symbolizing filial devotion mysteriously appears.

Leaving Gyotoku, the three warriors take Nui's infant son Daihachi and set off for Otsuka village. Back in Otsuka, Sosuke faces a death sentence after being charged with the murders of his step-mother and father. After getting wind of this, Shino and Genpachi go to his rescue. Under cover of night, the two sneak onto the killing ground and hide themselves. Then, just as Sosuke is about to have his punishment of crucifixion carried out, they pounce... Will they succeed in their quest to rescue Sosuke and escape to safety?