The only way to escape is to clear the game. Game over means actual death.

The ten thousand who have logged onto the as of yet mysterious game 'Sword Art Online' have been forced into this perilous death game. Protagonist Kirito, one of the many gamers, has greeted this truth. He plays as a solo player in the giant castle that is the stage for this game--Aincrad. To meet the conditions of clearing the game--getting through all 100 floors, Kirito fights his way through this quest alone.