Thousands of dungeons arose all across the planet one day. “The Dungeon Era,” also known as the “Age of Dungeons and Monsters,” befell humanity. Humans used horrible methods to kill Aldslay, a boss from an Abyss-Level dungeon. Aldslay, enraged and reluctant to accept it, resurrected as an inept player and mistakenly activated the one and only “Boss Player System.” He is able to conquer many dungeons and become the Dungeon Master with the help of the system. The path to vengeance has begun!