This .hack show takes place entirely in the real world unlike the other two series. This how is about this girl named Mai and her trying to figure out why her boyfriend went into "the World" with her and went into a coma.

                    The show starts off with Mai and her boyfriend Tomonari going into the world then him ending up in a coma. So she decides to start an investigation on why he went into this. During her investigation she meets a man named Junichiro a man who also believes that the world has been causing these problems. So they decide to recreate the same scenario Mai and Tomonari were in when it happened. So they used the same characters same computer and same area. All seems fine when mai hears a high-pitched noise she recognizes this noise from before and takes off her headset but junichiro is already getting messed up. Mai takes the head set off but its too late he was knocked unconscious. She takes him outside and luckily the rain woke him up. But that last experience did not tell them much. Their investigation has just begun. 

Overall- 9/10 Well for 4-part OVA this is pretty intense it solved .hack//Sign's problem of a long dragged out mystery by cramming it into 4 - 45 min eps.