Setting .hack//G.U. takes place in an alternate version of
Earth in the year 2017. As depicted in the first
.hack game series, the "2nd Network Crisis" was an incident that occurred seven years ago in which many computer systems across Japan malfunctioned. Through the efforts of those games' hero, Kite, the incident resulted in the birth of Aura, the
ultimate artificial intelligence (
AI), capable of making decisions for itself. Under the guidance of Aura,
The World, the most popular MMORPG at the time, flourishes and the events of
.hack//Legend of the Twilight occur during this four-year period. In late 2014, Aura disappears, resulting in the slow decay of
The World and the Internet as a whole. In response, the
company that administrates
The World, CC Corp, sets up "Project G.U." and tasks them with remedying the problem. They come up with the "Restore Aura (RA) Plan", in which they attempt to retrieve the fragments of Morganna—an AI that served as Aura's "mother"—and seal them into
player characters (PCs) of
The World. In theory, this would allow the Project G.U. programmers to manipulate the Morganna program to recreate Aura. Only certain "chosen" players could control these special "Epitaph PCs". After locating candidates to operate the Epitaph PCs, the team proceeds to test the RA Plan despite concerns over "anti-existences" that might damage the Internet. The program fails catastrophically and destroys over 80% of the data for
The World. Instead of trying to salvage the data, CC Corp develops
The World R:2 and releases it to a new generation of players. However, this new game is less popular than its predecessor and becomes plagued by "
player killers" (PKs), players who target other players for fun and sport. The Epitaph PCs which had been lost during the RA Plan disaster resurface in the new version, attached to certain players of interest.
Characters The main playable character of
.hack//G.U. is
Haseo, a player of
The World whose friend Shino fell into a
coma after being attacked by a PK named "Tri-Edge" within the game. As a result, Haseo becomes obsessed with gaining the strength to defeat Tri-Edge and save Shino—he earns the nickname "Terror of Death" for his relentless hunting of PKs. As an Epitaph PC, Haseo is recruited into the new incarnation of Project G.U., which now handles
debugging of
The World. Yata, who played a key role in the events of
.hack under the name Wiseman, leads Project G.U., while other Epitaph PCs including Kuhn and Pi make up the rest of the group. Haseo's hostile nature attracts the attention of
Atoli, a member of the peace-loving Moon Tree guild, who resolves to befriend him. Haseo is also searching for
Ovan, Haseo's and Shino's former guildmaster who disappeared during
.hack//Roots under mysterious circumstances.
Story Vol. 1//Rebirth After months of searching, Haseo finally encounters Tri-Edge and attempts to kill him but is hopelessly outmatched. In the battle, Tri-Edge uses an illegal
skill on Haseo, Data Drain, which corrupts his character data and resets it to
level one. Lacking the strength he once had, Haseo meets two friendly players, Silabus and Gaspard, who invite him to join their
guild. Haseo is also approached by Kuhn and Pi who recruit him into Yata's organization of Epitaph PCs, players who can summon Avatars. This group's goal is to protect
The World from AIDA, a mysterious
software bug that has been infecting parts of the game which can only be defeated using an Avatar. During this time, Haseo is contacted repeatedly by Atoli, a gentle
healer from Moon Tree guild who tries to convince him to enjoy the game and its world more. He is brusque and standoffish with her because her character model strongly resembles Shino's but she persists in trying to befriend him. Haseo awakens his Avatar, Skeith, while fighting in a tournament and he prevails over the champion Endrance, who was being controlled by AIDA. After Endrance's defeat, Atoli finds a strange red mark made by Tri-Edge and falls into the portal it creates. Haseo, Pi, and Kuhn follow her through the warp and see her struggling to open a
locker in a white void. Tri-Edge ambushes them but they manage to defeat him. After he fades away, the locker opens to reveal AIDA, which infects Atoli.
Vol. 2//Reminisce Haseo and the G.U. staff find themselves trapped inside the game, physically unable to leave or
log out. Atoli recovers, but is rendered mute, able to communicate only through instant messages. Yata explains that AIDA has copied
The Worlds server, trapping everyone inside to experiment on them. They transfer everyone back to CC Corp's servers to escape. Ovan directs Haseo to gather the Epitaph PCs together to solve the mystery of AIDA. Shortly afterwards, Haseo is approached by a player named Alkaid, concerned for her friend Sirius, who has been possessed by AIDA. They enter into a tournament to fight Sirius, but Alkaid is ambushed by the AIDA-infected PK Bordeaux, which leaves her in a coma. Haseo requests Endrance's assistance for the rest of the tournament. They defeat Sirius and purge him of the AIDA that had stolen Atoli's Epitaph. With Atoli's Epitaph returning, she also recovers. However, her superior from Moon Tree, Sakaki, pushes her into a depressed fugue that leaves her vulnerable to AIDA again. Sakaki attacks his own guild to provoke Atoli into using her Avatar; he seeks to manipulate her and AIDA so he can gain control of the real world through the Internet. Haseo saves Atoli and defeats Sakaki after he purposely contaminates himself with AIDA in a last-ditch effort to gain control of the network. Following this, Ovan appears and reveals that he is the real Tri-Edge—his left arm contains the first hostile AIDA. The enemy that Haseo had believed was Tri-Edge is actually Azure Kite, one of three AIs that Aura had created to destroy the AIDAs. Ovan orchestrated Shino's and Alkaid's attacks and Sakaki's betrayal in order to push Haseo into becoming strong enough to kill the AIDA possessing him. Though Haseo succeeds in defeating Ovan, the coma victims do not recover.
Vol. 3//Redemption With AIDA corruption spreading throughout the Internet, CC Corp executives fire Yata from Project G.U. and replace him with Sakaki. Mad with power, Sakaki forces Haseo into a tournament filled with AIDA-corrupted PKs. Haseo prevails in the tournament and defeats Sakaki. Haseo and the others find Yata who awakens as an Epitaph PC. They meet Ovan's sister, Aina, who has been trapped in
The World after Ovan's AIDA attacked her. With all the Epitaph PCs awakened, Ovan challenges Haseo to another fight. In defeat, Ovan is able to use his Avatar's special ability "The Rebirth" which completely resets the Internet and cleanses it of AIDA, though he falls into a coma as a result. The G.U. members are saved by Zelkova, leader of Moon Tree, who reveals that Ovan's actions caused several comatose players to wake up, though others are still trapped within the game. Yata discovers the cause: an "anti-existence" called Cubia is trying to devour
The World, resulting in the death of all players. Aina summons Aura who hints to the party that the key to defeating Cubia is the eight Avatars. Haseo calls on all the players of
The World to help in defending against Cubia's minions. With the combined powers of the eight Epitaph PCs including Ovan's spirit, Haseo destroys Cubia. With Cubia gone, all the remaining comatose players awake and Haseo meets Shino once again. Upon meeting her, Shino motivates Haseo to be more honest with his feelings which causes him to pursue Atoli. A
hidden ending in the Forest of Pain shows Haseo a vision of Ovan; Haseo declares that they will meet again.
Vol. 4//Reconnection One year and three months after Cubia's destruction, Haseo learns from Pi that Ovan's body has been located in
The World frozen in ice. Due to Skeith becoming destabilized, Zelkova seals Haseo's Avatar. Haseo is unable to shatter Ovan's ice prison. Haseo then meets Kusabira who informs him of an attack on the Net Slum a few days before at the hands of a gigantic monster created by the game's network issues, Vegalta. Kusabira tells Haseo that Vegalta has consumed Zelkova, her brother, and asks Haseo to save him before he dies. Haseo confronts the monster and frees Zelkova, who remarks that he does not have a sister but surmises her true identity. Kusabira is a remnant of AIDA that had developed human-like AI, and she called him her brother because he, too, is an AI native to
The World. Zelkova uses Kusabira's data to pacify Skeith's power and unseals the Epitaph, unlocking Haseo's final form and granting him access to the powers of all the Epitaphs at will. Haseo successfully destroys Ovan's ice prison with this new power. Kusabira appears and merges with Ovan, reviving him. Vegalta returns and faces both Haseo and Ovan. With their Epitaphs merged into one being combining Skeith with Corbenik and the others' powers, the duo destroys Vegalta. Ovan reunites with his sister and friends. On the last day of service for
The World R:2, Haseo logs on and speaks with each of his friends to say goodbye to the game and them. Ovan invites him on one last adventure through a dungeon and they reflect on their memories together. ==Development==