Akira Oono is an ordinary working adult who manages the MMORPG Infinity Game. Fifteen years after creating the game, Oono decides to shut the servers down once and for all. However, as the clock strikes midnight, he somehow finds himself in the body of middle-aged Hakuto Kunai, Infinity Game's Demon Lord! Soon after his mysterious transportation, he witnesses the demon Greole chasing after a little girl named Aku. Al...