Aliens have made their way to Earth and are now coexisting with humans in the 21st century. Mayuko, a destitute student residing in Enohana, unexpectedly finds herself living with NieA, a member of the lower caste of aliens known as "Under Seven." Although Mayuko strives to make ends meet, NieA appears indifferent towards the repercussions of her behavior. As their peculiar pairing creates friction, a damaged alien spacecraft looms in the distance.