Ten thousand players log into the virtual reality game Sword Art Online and find they cannot log out. Creator Akihiko Kayaba tells them the only way out is to clear all hundred floors of the floating castle Aincrad, and that dying in the game kills them for real. Solo player Kirito throws himself at the front lines and crosses paths with the skilled fencer Asuna, and the two slowly begin working together against the death game. This manga adapts the first Sword Art Online light novel.