In modern times, extraterrestrial beings have arrived on our planet and reside alongside humans. A destitute high school student named Chigasaki Mayuko is now sharing a home with NieA, an alien from the "Under Seven" caste. Despite facing financial difficulties, Mayuko strives to make ends meet. Meanwhile, NieA appears indifferent about the repercussions of her actions. As this unlikely duo navigates their differences, the wreckage of their damaged spaceship remains a looming presence in the background.