Sword Art Online

A virtual reality gaming console known as the "NerveGear" is released to the public alongside the world's first virtual reality game called "Sword Art Online" (SAO). A beta-tester named Kirito logs in and visits Aincrad, the setting where the game takes place, and quickly befriends a fellow novice player named Klein, to whom he teaches the basics of the game, including how to defeat a boar. A few hours later, Kirito and Klein discover that they cannot log out. Akihiko Kayaba, the game's creator and employee of the computer corporation Argus, announces to the players that he intentionally removed the option to log out and that players will die if either their NerveGear helmet is forcefully removed or their in-game health bar is depleted to zero. He also admits that he created this game as a way to become God over his own dominion, and that the only way to log out of the game is to clear all of Aincrad's 100 Floors.