Five years ago, Musashi made a promise with his friend Kojirou Kanemaki that they would become samurai, form a league, and go on demon-slaying quests. But since then, with demons now being praised and worshipped, the samurai are shunned and disgraced by society. Afraid of revealing his dream, Musashi blends into the town's dogma while secretly polishing his swordsmanship. As to Kojirou, after struggling and lost, he still embarks on a journey with Musashi in the hopes of figuring out his true feelings. The duo dives headfirst into the unknown world of beast-slaying, not knowing what life has in store for them...