After living peacefully in the caverns of a small town, a stranded group of aliens turn deadly as they fight for their existence, betraying the passionate chief of police who has protected them for 28 years.

故事的舞台是经历了阿提米斯神失落的月球崩坏的地球，从那以后已经经历几百年。复兴历107年，为了处理从月球上掉落到地球上的碎片，人们制造了被称为「iDOL=陨石除去人型重机」的机械。被选中的少女们被培养成「偶像大师」，来搭乘这些「…