Ash, a young man who once flourished as a Captain in the Imperial Knights and was engaged to a noblewoman, was living a life envied by all—smooth sailing and successful. However, one day, he was handed both a broken engagement and an order of expulsion from the Imperial Knights. Utterly disillusioned, Ash leaves the Empire and journeys toward the new world of the Rosabelle Kingdom. In this nation, which has surpassed the Empire in prosperity thanks to the power of its dungeons, Ash restarts his life as a Hunter. He quickly makes a name for himself, rising through the ranks with his overwhelming strength. Meanwhile, his junior, Ulka, who deeply respects him, chases after Ash and heads toward the Kingdom. The tale of reversal that will repaint a gray life is now beginning.