Yuuto Niboshi is 30 years old who had lost his parents in an accident at an early age. He lives in a large Japanese house with his grandfather Kozo. He has never been to work. He earned a living in the real estate industry and has only taken care of Kozo, who is sick, and his two cats, Kuro and Char, who live with him. One day, Kozo suddenly died of cerebral infarction. Kozo's death left Yuto and his cats to be left behind. Among the funeral, Yumi Hirose of Yotsuba Real Estate says that she is in charge of real estate management from Kozo. In addition, she will give up most of the real estate to pay the inheritance tax. If she has no income, she is offered to remodel the house into a share house where she lives with cats. However, for Yuuto, the cats are a family. Can residents and cats live together? Is it possible for Yuuto to live with others in the first place?