In 2022, a virtual reality massively multiplayer online role-playing game (VRMMORPG) called Sword Art Online (SAO) is released. Beta-tester and solo player Kirito re-enters the game, only to find out that the creator, Akihiko Kayaba, has trapped him and the other thousand players in a death game. Kirito now must fight to clear the game and stay alive inside the steel castel of Sword Art Online called Aincrad.