Feudal Japan is attacked by beasts called Youi'. Ryuudou Yukiatsu, a floater and an employee at a bath house has the power of Ayagami (The power to find the words behind things) which can be used in fighting against the Youi. That's why the members of a Youi-fighting group Bansha Aratamesho, called the Ayashi, are looking for Yukiatsu - they want him to become an Ayashi as well. Yukiatsu runs into a woman and a son who are chased by a Youi and has to face the past he's been running away from. (Source: ANN)