Nestled within Tokyo's Asakusa district lies a quiet mansion known as Ayakashi-sou. Despite its size, the mansion is home to just a single sixteen year old girl, However, Ayakashi-sou takes its name from the ayakashi— Japanese spirits and ghosts who inhabit it. Kuuko and Yukime, a prank-loving fox girl and gentle snow-woman, call this place home, while the childlike Zashikiwarashi Kii watches over the building. They are soon joined by the newly created cat youkai named Nene, who has nowhere else to go.

Living with the ayakashi is the building's owner, Mahoro Miyatsuka, who inherited it from her late grandmother due to her ability to see and interact with the spirits. While her ability allows her to connect with the ayakashi, Mahoro's habit of talking to invisible people has led to her peers avoiding her. Despite this, Mahoro is content with tending to her ghostly friends as they spend their days watching fireworks, playing games, and otherwise living life one day at a time.