During the Edo period, the samurai Toyohisa Shimazu valiantly leads his troops in a fierce battle against the renowned Tokugawa clan to secure the Shimazu clan's retreat. Despite the tragic loss of his comrades, Toyohisa bravely holds off the enemy alone, sustaining fatal injuries in the process. As he walks away from the battlefield in despair, he inexplicably enters a white corridor and is thrust through a door into a new world. Here, he meets other fallen warriors known as 'Drifters,' all gifted with exceptional abilities. United by a common goal, they combine their past wisdom and skills to challenge a malevolent force aiming to obliterate humanity and claim dominion over the land.