Twenty-two years ago, an unusual environmental occurrence took place in Kanazawa prefecture, causing the land to fracture and rise to unprecedented heights, forming an isolated region known as The Lost Ground. Kazuma is a young freelance soldier who resides in this unforgiving environment and does whatever work he can to make ends meet. He possesses the rare Alter ability, allowing him to cover his right arm and torso with a metallic alloy. When HOLY, an organization dedicated to restraining and capturing those they label as Native Alter Users, and one of their top members, Ryuho, cross paths with this mercenary, a legendary feud ignites.