In the 21st century, aliens have arrived on Earth and live among humans. In sleepy Enohana, the dirt-poor student Chigasaki Mayuko finds herself living together with NieA, a low-caste ("Under Seven") alien. While Mayuko struggles diligently to make ends meet, NieA seems to be totally unconcerned with the consequences of her actions.

Note: An omnibus version was released under the name NieA_7 Recycle