Asuna Yuuki had never played online games until accidentally putting on the NerveGear for Sword Art Online, the world’s first VRMMORPG. She soon finds herself and other players trapped inside a game, where if a player dies in the game, they die in the real world. As she continues to live on in this world where death is always a step away, a solitary swordsman named Kirito appears before her.

Over a month has passed since 10,000 users were trapped inside the "Sword Art Online" world. Asuna, who cleared the first floor of the floating iron castle of Aincrad, joined up with Kirito and continued her journey to reach the top floor. With the support of female Information Broker Argo, clearing the floors seemed to be progressing smoothly, but conflict erupts between two major guilds who should be working together – the top player groups ALS (the Aincrad Liberation Squad) and DKB (the Dragon Knights Brigade). And meanwhile, behind the scenes exists a mysterious figure pulling the strings…