After his village is burned for a forbidden ore, seventeen-year-old Kaito flees into the wilds of feudal Japan — hunted by rival clans and deadly assassins. In a moment of madness, he ingests the ancient Organic Soulstone, bonding its volatile power to his very body.
Now marked as prey by all, Kaito must master his newfound steam-born abilities, survive the treacherous neutral city of Tsukikage, and uncover the lost secrets of the Soulstone — before it consumes him from within.