Twenty‑two years ago a bizarre geological event in Kanazawa Prefecture split the earth and pushed it upward to record heights, giving rise to a hidden zone called The Lost Ground. Kazuma is a young contract fighter residing there, scavenging for any job that will keep him alive amid the unforgiving terrain. He belongs to a rare group of Alter users, able to coat his right arm and torso with a metal alloy. When he confronts HOLY—a faction tasked with hunting down native Alter wielders—and meets its top operative, Ryuho, a fierce feud erupts. The Lost Ground relies on ingenuity; Kazuma trades metal for food. HOLY Alter users, Ryuho is feared as hunter. Conflict escalates into a duel that defines future.