The first virtual game world, and the setting of the first story arc. The world takes the form of a giant floating castle called Aincrad, with 100 floors in it. Each floor has a medieval-themed setting and a dungeon with a boss, which has to be defeated before players can advance to the next higher floor. Like most RPGs, it implements a level-based system. However, after the beta testing, the game's creator activated a system to trap the players inside the game, unable to log out; if players die in-game, or the helmets they used are removed, a strong electromagnetic pulse is emitted frying their brain and killing them. 

Without parent's permission Krystal Jung goes into the worlds first virtual reality game "Fantasy Art Online" To Krystal, this was just a fun joke. Krystal's parents demand their older daughter Jessica to go into there and get their younger daughter out of the game. 

The problem is, the two girls get stuck in the game only having one way out, completing the 100 floors, all without loosing their lives. 

But their is over 1000,0000,000 players in the system, how will Jessica find her little sister? Would the older girl have to complete this by  herself? OR what will happen if she stummbles acrooss the nooby Tiffany Hwang? Will she stop and help the girl or let her die? 

Suddenly, the game shuts off letting go all of the remaining players. How will they find eachother?

CREDIT GOES TO SAO FOR THE TOP PARAGRAPH.