.hack//Mutation
.hack//Mutation is the second in a series of four games titled .hack//Infection, .hack//Mutation, .hack//Outbreak and .hack//Quarantine. It is a "game within a game," a fictional massively multiplayer online role-playing game (MMORPG) called The World, for which the player does not need an Internet connection. Players can transfer their characters and data between games in the series. Each game comes with a DVD containing an episode of .hack//Liminality, the accompanying original video animation series that describes fictional events that take place simultaneously with the games. The games are part of a multimedia series called Project .hack that explores the mysterious origins of The World. The games, set after the events of the anime series .hack//Sign, center on a player named Kite who wants to find out why some users have fallen into comas as a result of playing The World. The quest evolves into a deeper investigation of The World and its impact on the stability of the Internet.
Story
Kite and BlackRose return to the Θ Chosen Hopeless Nothing, but find part of the area locked. After a quick intervention with Balmung, the two return to Dun Loireag, where Kite learns that his Book of the Law, which he won in the level-up campaign, has a bug that prevents it from being installed. BlackRose claims never to have heard of this event. The two receive emails asking them to come to the Θ Soaring Sky Bounded Abyss if they want to learn more about the coma victims. In reality, it is a trap set by the system administrator Lios. Lios tells them not to pursue the matter further and deletes Kite's character data along with the bracelet. Helba, however, interferes and says that the data cannot be deleted because there is a mysterious encryption built into the character data. She theorizes that the world is based on the Epitaph of Dawn and advises the two to look for clues in the Epitaph. She then suggests to Lios that he watch the two instead of trying to erase them. Lios finally agrees and decides to use the two and the bracelet's unique abilities to investigate the tainted areas.