"NieA_7" is a 13-episode anime series set in a near-future Japan where extraterrestrial beings, known as the "Under Seven" (UFO aliens), have integrated into human society. The story takes place in the rural town of Enohana, where humans and aliens coexist, albeit with some tension and prejudice. The aliens are categorized into classes based on their social status, with the "Under Seven" being the lowest class, often living in poverty and facing discrimination.

The protagonist, Mayuko Chigasaki, is a hardworking and reserved college student who struggles to make ends meet while living in a run-down bathhouse. Her life takes an unexpected turn when she becomes the reluctant caretaker of NieA, a carefree and eccentric Under Seven alien who has taken up residence in her home. NieA is lazy, self-centered, and often causes trouble for Mayuko, but her presence gradually brings a sense of chaos and unpredictability to Mayuko's otherwise mundane life.

The series explores the daily lives of Mayuko and NieA as they navigate their unusual living arrangement, along with the quirky residents of Enohana. Mayuko works part-time jobs to support herself and NieA, while also dealing with the pressures of her studies and her strained relationship with her family. NieA, on the other hand, spends her days scavenging for food, tinkering with her makeshift UFO, and occasionally causing mischief around town.

Throughout the series, the narrative delves into themes of coexistence, identity, and the struggles of marginalized groups, using the alien-human dynamic as a metaphor for societal issues. The interactions between Mayuko and NieA highlight the complexities of their relationship, blending moments of humor, frustration, and subtle emotional depth. Supporting characters, such as the bathhouse owner Karna and the enigmatic alien Chada, add further layers to the story, providing insight into the broader social dynamics of Enohana.

The tone of "NieA_7" is a mix of slice-of-life comedy and subtle social commentary, with a focus on character-driven storytelling. The series avoids grandiose plotlines, instead opting for a more grounded and introspective approach that emphasizes the everyday struggles and small victories of its characters. The result is a unique and understated narrative that captures the nuances of life in a world where the extraordinary becomes ordinary.