This story begins on the closing day of the popular online game Yggdrasil. Our main character, Momonga, decided to stay in the game until the very last moment, so he began to wait for a forced disconnection from the server. However, the server did not interrupt the connection and Momonga was stuck in another world in the skeleton avatar. Now the “mighty overlord" needs to explore the new world and go through many trials that he will meet. Without parents, friends, or social status, this ordinary guy decides to take over the new world the game has turned into.