Since ancient times, Japan has upheld the tradition of the 12 Zodiac signs. Eto-musumes (Zodiac girls), who have the appearance and behavior of the animals of the Zodiac, are pure hearted messengers who act as a bridge between humans and the gods. Every 60 years, the “ETM 12” tournament takes place in Tokyo’s Akihabara district, where aspiring girls from all over Japan gather for the chance to become the next zodiac sign.
Commonly known as the "Dungeon," the city of Orario possesses a huge labyrinth in the underground. Its strange name attracts excitement, illusions of honor, and hopes of romance with a pretty girl. In this city of dreams and desires, new adventurer Bell Cranel has his fateful encounter with the tiny Goddess Hestia.
Thus begins the story of a boy striving to become the best adventurer and a lonely goddess searching for followers both hoping to reach their goals and perhaps have some romance on the side.