there problem there two thing you must know
1 you need buy the game to learn the or read the manga
2 is watch .Hack//Sign
Quantumn,Illuminati and .Hack//roots and the game ps2
.Hack//G.U. Vol 1,2,3 and movie trilogy
Just go with what the person above said. But me when i first watched Hack it was the Hack//Trilogy movie. I watched in english subs. Cause Netflix has english subs of the movie only. And at the time 3 or 4 Years ago i was new to Hack and diden't know what to expect. But i started likeing Hack// after watching Hack//Trilogy with my little brother. And my little brother also liked Hack// just like i do.
