Sword Art Online (Japanese: ソードアート・オンライン Sōdo Āto Onrain?)
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 to kill their real bodies.
You can get all parts of the series by clicking on the links below! For part 1, 2 , 3, 4!
Part 1- Sword Art Online DVD I: Aincrad Part 1