Many years have passed since the ALLTYNEX incident and humanity’s resettlement of the Earth. The world’s nations have joined to form a unified economy and a global militaristic government. However, in opposition to the worldwide mass oppression, a resistance organization arose: Valkyness. The decades long conflict between the Global Unified Army and Valkyness is suddenly interrupted when an alien force arrives seeking vengeance on humanity for atrocities inflicted upon their people. Earth's war against the Raiwat leads to a surprising ending that reduces almost the entire planet to scorched earth, brings mankind to the verge of extinction and sows the seeds of the events to follow in KAMUI.