Behind the bustling splendor of the modern city lies a secret world inhabited by monsters from the Classic of Mountains and Seas. These monsters live in harmony with humans. Some have become celebrities, some run major corporations, and others work as ordinary police officers, delivery couriers, and laborers. They blend into society as humans, but each possesses unique abilities. The story follows these monsters' daily lives, revealing how they search for themselves and maintain the balance in the human world, as well as the mystery and adventure hidden behind the city's dazzling facade.
