Sword art online

"Kirito and Sinon's battle with Death Gun is over, but mere weeks later, something strange is afoot in the next-generation VRMMO ALfheim Online. A new duelist with a custom sword skill is defeating all comers--including Kirito. But when Asuna goes to face this duelist, she receives something she never expected: an invitation to an exclusive guild. But what is their goal?"--Amazon.com.