Hack//Sign

.hack starts in a fictional 2005, introducing a computer virus called Pluto's Kiss as the cause of a massive Internet shutdown. The results are described as catastrophic: traffic lights shut down, planes collide in midair, and the United States' nuclear missiles are nearly launched. As a consequence, cyberspace is subjected to severe restrictions. The virus affects all operating systems except for one, Altimit OS, the only operating system immune to all computer viruses. Two years later free access to the networks recovers, bringing with it the release of The World: the first online game since Pluto's Kiss, developed for Altimit OS. The World is portrayed as a fantasy setting wherein player characters can be different classes, adventure by themselves to go searching through dungeons, or join with others and form parties; fight monsters and level up, collect new items and participate in special events. At the center of each server is a Root Town, which contain shops, a save point, and the Chaos Gate that players use to travel between servers in the game.
Harald Hoerwick is introduced as the creator of The World. He secretly designed the game as a virtual womb in order to create the ultimate artificial intelligence (AI), by receiving emotional and psychological data from the players. His motivation is revealed to be the death of Emma Wielant, a German poet whom he was in love with; the AI, who was named Aura, would serve as the "daughter" they never had. Harald left the gathering of the required data for Aura's development at the care of the core system of The World itself, an omnipresent AI called Morganna Mode Gone. Most of the events depicted in Project .hack revolve around the premise of Morganna attempting to stall the growth of Aura indefinitely, after realizing that she will lose her purpose once Aura is complete. This sets the background for the storyline of .hack//Sign, that takes place in early 2010.