Freed from the rule of samurai 150 years ago, the people of Hinomoto live peaceful lives and revere the mysterious demons who liberated them. Musashi knows the grim truth: humanity is enslaved by these otherworldly beings, and the samurai are the last ones fighting for freedom. Musashi hides his true opinion from his peers, and grows distant from his childhood friend Kojirou Kanemaki.
On the day of his graduation, Musashi and his peers arrive at the mine, horrified to see the inhumane treatment of miners and the uncanny physical appearance of their overseers. Kojirou helps Musashi endure the harsh conditions. Then, the demon leader wreaks havoc on the quarry, and Musashi is saved from certain death by the Takeda samurai clan.
Humiliated and yearning for adventure, Musashi embarks on a journey to become a samurai, and form his own clan!