After losing their parents, Han Yujin and Han Yoohyun, unusually close siblings, navigate a world altered by the emergence of deadly dungeons. Yoohyun evolves into an overpowering S-rank hunter, while Yujin struggles as an F-rank with ordinary abilities. Despite being shut out for years, Yujin's desire for reconciliation leads to unexpected transformations and a chance at peaceful coexistence. As he attracts the attention of elites, Yujin embraces his role in supporting a growing circle of influential figures.