Sword Art Online Unital Ring, Vol. 1 (manga): Volume 1

Orchestrated by genius scientist Akihiko Kayaba, the "SAO Incident" created a game you couldn't leave until you beat it. One where death in the game meant death in the real world... Kirito is a survivor of SAO, who now spends his time playing the new VRMMORPG Alfheim Online with his old SAO friends, Asuna and Alice. But their fun is short-lived, as Kirito soon finds himself in a mysterious game that defies everything he once believed possible...