Lemuria, the City of Adventurers.

There, an adventurer was challenging the world's oldest dungeon, "The Spire of Hihi."

Other than being an outsider, an unremarkable, ordinary person with no companions, who hadn't achieved a single success even after a decade.

Eventually, when their only sword broke and they resigned themselves to the end, a snake appeared before the adventurer.

The snake, claiming to be an ancient king, grants power to the adventurer who has nothing... but the price was by no means small.