High school student Dan spends his days feeling trapped by the constant misunderstanding that he is a delinquent due to his intimidating appearance. One day, he finds an abandoned kitten and cannot bring himself to leave it, so he takes the stray home. While caring for the cat, it suddenly transforms into a man with cat ears. The creature reveals himself to be Nia, an alien from the planet Nyaon. Nias stated goal is an outrageous one: to enslave humanity for the purpose of securing a life of complete idleness. Despite this bizarre premise, Nia ends up staying in Dans home. As they live together, Dan gradually begins to feel at ease in Nias company, discovering a sense of comfort and warmth he had been missing.

The story is a relaxed and happy同居 (cohabitation) love story set in contemporary Japan. The narrative arc follows the unexpected domestic life of a cool, hardworking boy and a selfish alien who takes the form of a cat boy. Nias original mission to conquer Earth by enslaving humans to do all his work for him slowly evolves. Through his time with Dan, Nia discovers the satisfaction that comes from earning a living and being praised for a job well done, finding that pure laziness is ultimately unfulfilling. Meanwhile, Dan, who has been carrying the loneliness of living without his parents, rediscovers emotional warmth and begins to find more purpose and joy in his daily life. The manga concludes with the sixth and final chapter, bringing this story of an arrogant alien cat and a misunderstood working boy to a close.