The plot of the games follows the story of the .hackers Kite (カイト) and Black Rose (ブラックローズ) and their attempts to find out what caused the sudden coma of Kite's friend, Orca (オルカ).
Included with each game is an extra DVD containing an OVA from .hack//Liminality.
The .hack games are particularly unique for their ability to share save data between each release, upgrading it for each release to make it playable and carrying over save data for such.
The four volumes that comprise the series of games are: