The players of a virtual reality MMORPG, Sword Art Online, are trapped and fighting for their very lives. After it is announced that the only way to leave the game is by beating it, Kirito - a very powerful swordsman - and his friends take on a quest to free all the minds trapped in Aincrad.
After putting an end to the SAO incident in the year 2022 and rescuing Asuna in ALfheim Online (ALO), Kazuto Kirigaya finally returned to the real world to resume a normal life with his friends once more. However when a string of deaths begin occurring in connection to a virtual reality game called "Gun Gale Online" (GGO), Kikuoka Seijiro of the Ministry of Internal Affairs enlists Kazuto to once again don his character "Kirito" and enter the virtual world to investigate the cause of the deaths. While meeting new allies, Kirito may be faced with his most dangerous challenge yet a player known only as "Death Gun" with the ability to kill a person in the real world by killing their virtual avatar.