One year after the SAO incident was resolved, Kazuto Kirigaya is adjusting to a normal life once again as best he can. He thinks all that death is finally behind him, until he is approached with some startling information. In the wildly popular pro shooter MMO Gun Gale Online, an ominous player has shot players in the game, and the same players mysteriously turned up dead in real life. Kazuto feels himself being pulled in as if by the shadow of SAO and agrees to investigate. He must now tread back into the dark world of his past with the help of the troubled, ice-cold sniper Sinon as he searches for the player who only refers to himself as "Death Gun."