Edo period, Japan. A young warrior, Jinta, has dedicated his life to the protection of a priestess in a remote mountain village. When demons appear and threaten the shrine, Jinta is tasked with entering the forest to hunt them down. But the mysteries he uncovers there change his fate forever, and send him on a journey traversing space and time. Jinta's dark destiny will carry him through hundreds of years of history, as he struggles to answer a single question: why does he wield the sword?