Lord Mibu gathered performers to play in Isozuki's Forest. Asagi is a koto player serving Lord Mibu who contracted a sickness which caused her body to dry up and crumble to dust. Since she could no longer serve Lord Mibu, she left the forest (of her own accord) and 'Janome', her umbrella-holder and bodyguard, carried her with him, in a special gourd. She is able to possess people and this slows down the sickness, so Janome assists her, though somewhat against Asagi's will, in finding a host.

Spoiler

Janome/Akagane is trying to get Natsume to cooperate, so that Asagi can play for Lord Mibu in Isozuki's Forest one more time, when the full moon will expose the path to the forest. In reality, Asagi just wants to play for Janome, who loves her and has taken care of her and protected her for so long.