This is pretty much the plot through the games. The first spoiler doesn't contain many spoilers, but the second contains the end of the series. Click with precaution
.//Hack is originally about a boy who joins an MMORPG called The World. It is very advanced, and seems like you are actually in The World by the use of a special headset. The boy created a character named Kite and quickly got into the game. Since the beginning of The World, it had started growing a mind of it's own because it was so advanced. AIs started acting out of whack, and some became dangerous. People were reportedly going into comas all over the real world, all because of bugs in the game. Throughout a series of events, Kite gains the Twilight Bracelet, a close friend of his goes into a coma, and he gains a new companion, Black Rose.
With this powerful, new weapon, Kite began investigating the strange events plaguing The World, and began to discover clues left by the game's enigmatic creator, Harald Hoerwick. With the help of his allies, Kite began to piece together the true nature of The World. With his friends by his side, he battled against Skeith and the other seven Phases of the Cursed Wave, endured system crashes, and even fought against his own dark reflection, the anti-existence of his bracelet, Cubia. Forming an unlikely alliance between his party, the hacker Helba, and the system administrator Lios, Kite formed the group that would later be known as the .hackers.
Together they penetrated into the very core of The World and brought about the rebirth of the ultimate A.I., Aura. Through his actions and the actions of his friends he was finally able to free Orca from his coma along with the other victims, bringing a golden age to The World.
No. That's the plot for the game series, which was the main plot the anime was based off of... probably should have mentioned that.
Legend of the Twilight was about a brother and sister who had been separated at an early age winning a contest. They had won the Kite and Black Rose character models in The World. Then, Shugo (Brother who plays with Kite's model) gains the twilight bracelet directly from Aura directly. His sister's name in Rina, btw. XD
Yeah, it was... I wish they would make a series based off the games' plot. It would be a hit, I bet. Also, the reason Legend of the Twilight ended at 12 episodes is because it was cancelled, I'm pretty sure. It was at 4AM on Adult Swim, and nobody wanted to be up at that time to watch it. XD
Bold means i'm finished.
Strike means I stopped watching
Regular means I just haven't finished it yet.
Furi Kuri/Fooly Cooly Neon Genesis Evangelion w/ ending movies Panty and Stocking with Garterbelt (thx Snowy) Nixed because it became retarded.
Dokuro-Chan (thx Kinetic) Lucky Star Excel Saga Fullmetal Alchemist
Fullmetal Alchemist Brotherhood Cowboy Bebop
Gintama Blood+ Inuyasha (including the final arc) Azumanga Dioah Nixed because the episodes became increasingly stupid. Code Geass
Ghost in the Shell: Stand Alone Complex
Blood Princess
La-Mulana
K-On! Astro Boy (1950's series) Samurai Champloo
Beelezub
Madoka Magica Fruits Basket
Fairy Tail School Days Gurren Lagann In all honesty (DKH), I just thought the series was very slow and boring.
Ninjama
I've finished a few recently:
The Monogatari seires (Bake, Nise, and Neko) sans Season 2
Chuunibyou demo Koi ga s***ai!
Gurren Lagann
Neon Genesis Evangelion
Nichijou
Panty and Stocking
Gintama season 1
Shirokuma Cafe
I know I've seen more but this is all I remember from the past year or two.