After nine years of playing the game "Dungeon and Stone," the main character, Lee Hansoo, finally reaches the boss level, a feat no one has accomplished so far. However, upon entering the boss room, he receives a warning message indicating that he has completed the tutorial phase and now possesses the body of the notorious figure, Bjorn Jandel, a controllable character in the game. In the world of "Dungeon and Stone," only one city stands amidst the destruction. A dungeon opens every month, offering adventurers a chance to overcome it for rewards. In this world, where those possessed are deemed useless in everything but combat, failure to fight means certain death. If unable to pay exorbitant taxes demanded by the city, the only fate awaiting is being downgraded to a "lower-class citizen." Being discovered as the owner of the character one is role-playing as results in being labeled a "demon" and killed. Lee Hansoo's only way to survive is to enter the dungeon and fight regardless of the life-threatening dangers. With skills accumulated over nine years of gaming and a foolishly strong possessed physique, he strives to survive in this game.