The anime is set in the year Mobile Century 8013 and depicts a world where humans have been absent from Earth for over 7,000 years. The only beings that remain are military robots who have been engaged in perpetual conflict with no hope for resolution. The fighting even extends across continents, plaguing the Rebellion Federation of Europe and the Principality of Shin in Asia. Despite the grim circumstances, three brave young robots initiate a movement to put a stop to the senseless battle and bring about positive change.