In 2061 AD, Japan is dominated. Divided and ruled by the four major economic blocs of the world, the Japanese people spent their days oppressed as subjugated citizens. Japan became the front line of the world where AMAIM, a human-type special mobile weapon deployed by each economic zone, strode about.. One day, Amou Shiiba, a boy who loves machines, meets i-LeS (autonomous thinking AI) named "Gai," and this leads him to throw himself into the battle to reclaim Japan, by piloting the AMAIM "Kenbu" built by himself.