Far-future Earth has reached a level of technological development that makes daily life genuinely stable. Then Goldibus — an alien tyrant with specific conquest ambitions — arrives with a force large enough to threaten the entire planet. An improvised coalition forms: each member brings their own mecha and their own reasons for fighting. The variety of machines and motivations makes them unlikely allies, but Goldibus has given them a shared objective. They will not stop until the invasion is stopped.