In the .hack universe, the G.U. series will take place in the year 2017, seven years after the events of the previous four titles. Since the events of the previous games, a cataclysmic event has caused "The World" to begin to evolve on its own. "PK's" (player killers) are now roaming the world, though it is not sure how they have come to be. Essentially, "The World" has become more unstable and uncontrollable. Yet, people keep playing.
.hack//G.U. is actually planned to be not one game, but three. However, unlike the previous four .hack games, these three "G.U." games will be their own game. Matsuyama commented that the previous four games were different only in regards to the plotline, but shared basically the same graphics, environments, music, etc. However, the G.U. titles will each have their own environments, new characters for each game, and new music. In other words, each game will truly be a separate game, not three parts to the same game (as many fans found to be the case of INFECTION through QUARANTINE). We were also told that the first part of the three-part G.U. series is already larger than the four previous games combined, which should allow for a longer and more enjoyable game experience.