In the year 2005, a computer virus called 'Pluto's Kiss' completely shuts down the global internet network.

In 2007, after extensive restructuring of the network, an online network game (MMORPG) called 'The World' is created and released.

Tsukasa, one of the game's players, suddenly awakens to find himself in 'The World,' able to feel, smell, touch, see and hear everything as if he was really there.

Almost immediately, he is approached by an in-game 'justice' organization, the Scarlet Knights, who try to capture him because they suspect that he has been working with hackers due to the tweaked character he was seen with.

His attempts to logout fail and he is stuck in 'The World.’

Unable to remember what happened before he awoke, he wanders around aimlessly. While doing so, Tsukasa finds a magical item that grants him the power to use a fearful 'Guardian' that will protect him from danger. Incidentally, this Guardian is capable of causing real world harm to other gamers.