.hack (pronounced "dot hack") is a massive multimedia franchise initially released in 2002. Media releases span 2002 through 2022, and the series is currently celebrating its 20th anniversary. The franchise has released light novels, manga, anime, video games, trading card games, toys, live events, webcomics and webnovels, soundtracks, and much more. The series is is developed by CyberConnect2 and the games are published through Bandai Namco Entertainment.
The story of .hack takes place in an alternate timeline to our own, initially set in the near future at the time of release. While similar to our reality, several key events differentiate the history of .hack's world from our own. Near the turn of the 21st century, a catastrophic computer virus wiped out the net and forced world leaders to restrict access to regular citizens, allowing only government and business use of what network remained. In time, citizens are once more allowed to access the new network. The ALTIMIT OS (Altimit Operating System) is released to ensure greater security and avoid future security threats and widely adopted, gaining 100% of the market share for all computer systems around real the world in everyday applications and use from desktop computers, government systems, schools, phones, transportation networks, municipal and hospital systems
A company known as CyberConnect Corporation, commonly referred to as "CC Corp," (not to be confused with CyberConnect2) takes advantage of the dearth of network games and releases a MMORPG called "The World." As the first network game since the crisis, The World is incredibly popular, gaining over 4.5 million players on its first day before going on to having 20 million players by the time of the events that occur in the first set of games in the series.
The basis for The World was created by a German programmer named Harald Hoerwick, based on an epic poem called The Epitaph of Twilight, written by Emma Wieland. Harald sought to use the game to create the ultimate AI as the daughter he could never have with Emma after her untimely death. Unbeknownst to CC Corp, the development of the Ultimate AI was integrated with the game and was intrinsically linked with ALTIMIT OS and the network's vital operations upon which the majority of Earth's population now depends. As unexpected factors hinder the Ultimate AI's development, the network gradually becomes unstable and the effects begin blurring the boundaries between offline and online.
The shift is gradual enough that initially it can be handwaved away by CC Corp, but the frequency of incidents accelerates past the point of being concealed from the general public. Players start to see strange errors spread across The World. Rumors spread of invincible monsters, unusual abilities, and players falling into a coma while playing the game. Strange incidents escalate to the point regular players start to search for answers as CC Corp attempts to coverup the game's involvement.