Sword Art Online

In the year 2022, the Virtual Reality Massively Multiplayer Online Role-Playing Game (VRMMORPG), Sword Art Online (SAO), is released. With the Nerve Gear, a virtual reality helmet that stimulates the user's five senses via their brain, players can experience and control their in-game characters with their minds.

On November 6, 2022, all the players log in for the first time, and subsequently discover that they are unable to log out. They are then informed by Kayaba Akihiko, the creator of SAO, that if they wish to be free, they must reach the 100th floor of the game's tower and defeat the final boss. However, if their avatars die in-game, their bodies will also die in the real world. The story follows Kirito, a skilled player who is determined to beat the game. As the game progresses for two years, Kirito eventually befriends a female player named Asuna with whom he ultimately falls in love. After the duo discover the identity of Kayaba's avatar in SAO, they confront and defeat him, freeing themselves and the other players from the game.



Upon returning to the real world, Kirito learns that Asuna and a small group of SAO players have still not awakened yet. Following a clue about Asuna's whereabouts in another VRMMORPG called Alfheim Online (ALO), Kirito also logs in there. Helped by his sister Suguha, he learns that the trapped players in ALO are part of a plan devised by Nobuyuki Sugō to perform illegal experiments on their minds to put them under his control, including Asuna, whom he intends to marry in the real world in order to take over her family's company. After Kirito stops Nobuyuki's plans, he finally reunites with Asuna in the real world.

Soon after, Kirito plays another game called Gun Gale Online (GGO) to investigate the mysterious connection between it and deaths occurring in the real world. Assisted by a female player he meets in the game called Sinon, he identifies and exposes the culprits, who include some former members of a murderous guild he had previously encountered in SAO.



Kirito is later recruited to assist in the development of a state-of-the-art game, UnderWorld (UW), which has an interface that is far more realistic and complex than the previous games he had played. In UW, the flow of time proceeds thousands of times faster than in the real world. However, he ends up falling into a trap set by one of the murderers from GGO and wakes up inside the game, unable to log out, with his real self left in a comatose state. As he starts to question if he is the real Kirito or an artificial intelligence modeled after him, Asuna, Suguha and Sinon also log themselves into UW in an attempt to help him.