In 2022, the virtual role-playing game "Sword Art Online" launches, allowing players to fully immerse themselves in the fantasy world of Aincrad. Through a technological device called NerveGear, which can influence sensory perceptions, gamers experience the game as reality. One of the 10,000 chosen players is Kirigaya. After successfully overcoming the initial battles, he suddenly finds himself unable to log out of the game. Shortly thereafter, the system's developers announce that players can only leave the world once they have defeated all the final bosses of the 100 levels of the game. Thus begins the action-packed journey...