Akiyuki lives on post-war Sentan Island, always rushing between the demands of his separated parents and his friends at school. But his carefree days come abruptly to an end when his school bus suffers an explosion, the first attack to plunge Sentan back into war. Akiyuki lives to find himself turned into a Xam’d, a mysterious creature, by the suspected cause of the explosion. Engulfed by Xam’d, Akiyuki is eventually saved by a red-haired girl, Nakiami, only to find himself torn away from those he loves. Now he must work to control and understand the creature within him, all while searching for his family and friends in a world steeped in the secrets and chaos of war.