In the year 2022, virtual reality has advanced by leaps and bounds, and Sword Art Online (SAO), a major online role-playing game, is released. Players may manage their avatars within the game using only their thoughts thanks to "NerveGear" technology. Kazuto Kirigaya, dubbed "Kirito," is one of the lucky few gamers who got their hands on the game's first shipment. He logs on to discover himself in the gorgeous and intricate world of Aincrad, which is full with magnificent medieval weapons and horrible monsters, along with tens of thousands of others. However, the players quickly discover that they are unable to log out since the game's designer has locked them in his new world until they finish all one hundred levels.