In the turmoil of Edo, a city besieged by famine and unrest, ancient gods known as Youi emerge due to humanity's collective prayers and fears. Yukiatsu Ryuudou, masquerading as a wanderer and rogue for decades, conceals his true identity while wielding the power of Ayagami, which allows him to unveil and combat these supernatural beings. A fateful encounter with a Youi and the enigmatic Office of Barbarian Knowledge Enforcement compels Yukiatsu to confront his past and embrace his dormant abilities, embarking on a journey to vanquish the malevolent creatures that haunt the mortal realm.