It is a manga based Japanese animated show. In this we have the main protagnist whose name is Kazuto Kirigaya , the boy is called Kirito as his short name, the boy was an gamer who loves to play the video games. His idol who devlops games created a Virtual Reality game came Sword art online, for playing the the game you have to wear a nervegear .

After diving into the VR game our hero finds out that there is no log out menu, after the complete revelation he knows that it is a death game which was created to let people stay in this virtual world.

In this game it stores the surviving of our hero and his life in the game and the loss of friends , finding the true love . In game he has got some unique skills which was not discovered until end the name of the the skill was dual handed wielding which makes him much faster then the other player.

As the players progress through the game Kirito eventually befriends a young girl named Asuna Yuuki, forming a relationship with and later marrying her in-game. After the duo discover the identity of Kayaba’s secret ID, who was playing as “Heathcliff”, the leader of the guild Asuna joined in, they confront and destroy him, freeing themselves and the other players from the game.

In the real world, Kazuto discovers that 300 SAO players, including Asuna, remain trapped in their NerveGear. As he goes to the hospital to see Asuna, he meets Asuna’s father Shouzou Yuuki who is asked by an associate of his, Nobuyuki Sugou, to make a decision, which Sugou later reveals to be his marriage with Asuna, angering Kazuto. Several months later, he is informed by Agil, another SAO survivor, that a figure similar to Asuna was spotted on “The World Tree” in another VRMMORPG cyberspace called Alfheim Online (ALO). Assisted in-game by his cousin and adoptive sister Suguha “Leafa” Kirigaya and Yui, a navigation pixie (originally an AI from SAO), he quickly learns that the trapped players in ALO are part of a plan conceived by Sugou to perform illegal experiments on their minds. The goal is to create the perfect mind-control for financial gain and to subjugate Asuna, whom he intends to marry in the real world, to assume control of her family’s corporation. Kirito eventually stops the experiment and rescues the remaining 300 SAO players, foiling Sugou’s plans. Before leaving ALO to see Asuna, Kayaba, who has uploaded his mind to the Internet using an experimental and destructively high-power version of NerveGear at the cost of his life, entrusts Kirito with The Seed – a package program designed to create virtual worlds. Kazuto eventually reunites with Asuna in the real world after thwarting an attack from Sugou and The Seed is released onto the Internet, reviving Aincrad as other VRMMORPGs begin to thrive.