In a bustling coastal city, three youkai named Bem, Bera, and Barro sense a malevolent aura stemming from human immorality and mischievous monsters. Moved to action, they opt to remain in the city, battling monsters and youkai preying on humans while forming unlikely friendships. Despite enduring mistreatment for their non-human forms, the trio perseveres in safeguarding the city's populace, aspiring to earn humanity through their noble deeds.