Suddenly, her parents traveled abroad, and Souma Kohinata, a high school student who remained alone in Japan, decided to live with writer named Isourou Yuzuki. On the evening of the day she moved to the old mansion where Yuzuki lives, Souma suddenly meets a lovely little demon. In fact, in the garden of Yuzuki's house, there is a warehouse connected to the world of Ayakashi, and Yuzuki was the manager of that warehouse! From that day onward, the friendly youkai who began to gather around Souma. However, strangely, the youkai seemed to be familiar with Souma when she was younger.