One day, an ordinary high school student is transferred to another world. He raises his level in the other world, successfully defeats the Demon King, and saves the world! With his strongest status, he decided to return to his own world. However, in the world to which he returns, a new "dungeon" has appeared. A modern dungeon fantasy where the former hero becomes a warrior, delving into dungeons created in his own world! (Source: Kadokawa, translated)