Akira Oono is a regular working adult who oversees the MMORPG Infinity Game. Oono chooses to shut down the servers once and for all fifteen years after inventing the game. However, as the clock strikes midnight, he finds himself in the body of middle-aged Hakuto Kunai, the Demon Lord of Infinity Game! Soon after his odd transfer, he sees the monster Greole running for a little girl named Aku. Despite dispatching the beast with ease, Hakuto is disturbed; after all, he has no recollection of creating either the girl or the demon! Hakuto chooses to explore, doubting whether he is genuinely in his creation's reality. Hakuto embarks on a trip with Aku as his guide and friend to discover who or what he is.