since they've been playing online games, the creators of Somnus Rift noticed them. The creators were scattered worldwide to look for players/gamers— frustrated, newbies, pros, etc. And all have one thing in common; they want to escape from reality. Just so happens that the main nine characters in the story would be the "chosen ones". The " bug" is that at the first weeks or so in the game, everything seems ordinary just as every games are(y'know, like SAO or Log Horizon). Until they get drawn to the game. Once that happens, a bug will occur. They can't log out anymore. And there's only one way out; to kill the bug. It could be a monster, a player, a NPC, or they themselves. Most try to escape from the game by death. And they never return— when they die in the game as the bug is there, they'd be put in an eternal sleep.