Chikashitsu Dungeon: Binbou Kyoudai wa Goraku wo Motomete Saikyou e

Countless dungeons that suddenly appeared all over the world. And the mysterious creatures that live there.
The government of each country were making every effort to investigate and manage "dungeons".
Meanwhile, a new dungeon suddenly appeared in the basement of the Boro family where Touka and Haruka, brother and sister living in poverty!
They begin to explore this dungeon on their own, looking for treasures and meat that monsters will drop…