By the time he realized what was going on, Yamagishi Amizuna, a salaryman, was in a strange cave, and in front of his eyes was a giant black tiger...!? When he thought his life ended after being attacked by the tiger, he awoke once again in the same place. Amizuna desperately struggled in an irrational situation without understanding the goal. It's a game where you have to use your own body to level up and beat dungeons He died countless times and was resurrected in the same place, drawing lessons one by one, while gaining more clues and the abilities to pass the stages .... All to get out of this crazy game... Return to Death x Level up. The actions that a salaryman must take in order to get stronger and survive!...