From the introduction:
This is a game about Keeton, wandering medicine master in a far-off land of older days. Keeton travels across the countryside to villages troubled by natural spirit creatures called yōkai, whose motives and actions are wholly alien to human thought. This game is inspired by the animated series Mushi-shi.
Keeton intently studies yōkai and knows their ways well. However, this does not always make his job easy. Helping a village troubled by a yōkai often requires sacrifices to be made by all, and some villagers resist that. Keeton must convince them.