The main premise of the story covers the happenings that Midori and Adamas witness and experience in The World R:2, an extremely popular MMORPG that is a new version of the original game, The World. Midori meets numerous characters from .hack//Roots (most notably Haseo,) and .hack//G.U. (such as Silabus and Gaspard.) The main plot centers around Midori selling herself out to would-be PKers, and some real-world events that center around the girl who also bears the name Midori who is in a coma.

Source: Wikipedia