After spending twelve years immersed in his beloved MMORPG, Momonga logs in for what he believes to be the final time, only to find himself permanently transported into the game’s universe. In this new reality, his character rises to become the Sorcerer King Ains Ooal Gown. The Sacred Kingdom, once thriving, now teeters on the edge of collapse despite years of tranquility secured by a massive wall that shielded it from neighboring threats. This peace is shattered when the Demon Emperor Jaldabaoth arrives with a horde of malevolent demi-humans. Faced with the threat of invasion, the neighboring Slane Theocracy is compelled to seek assistance from their adversaries in the Sorcerer Kingdom. Responding to their plea, Momonga, now the Sorcerer King Ains Ooal Gown, mobilizes the Sorcerer Kingdom and its undead forces to ally with the Sacred Kingdom and the Slane Theocracy in a bid to vanquish the Demon Emperor.