Yusuke, Kurama, Hiei, and Mitarai enter a cavern controlled by the tricky Gamemaster. Gamemaster's territory can be manipulated into a video game, a game where everyone must play by the rules in order to survive. Yusuke's team must win 4 rounds to move on, but is a victory possible against an adversary who can manipulate the rules?

Koenma's tactics have saved Yusuke for now. But mysteriously Yusuke won't allow the Prince of Spirit World to use his pacifier. While they discuss their next move, the terrible gateway between Demon World and Living World opens.

Control of Demon World is divided among three rulers: Raizen, Yomi and Mukuro. From his deathbed, Raizen has invited his descendant, Yusuke Urameshi, to return to Demon World to train under him for one climactic battle. Yusuke's first challenge is to defeat his ancestor. If he cannot defeat one of the three kings, how could he expect to stand up to the other two?!

Just as Yusuke and Hiei were forced to confront their demons, Kurama boldly ventures through his own past. Yomi, one of the three Kings of Demon World has summoned his former partner in crime to his inner sanctum. What secrets haunt Kurama? And why has Yomi prepared for the worst?

Yomi and Mukuro, preventing a full-scale Demon War, have embraced Yusuke's unlikely proposal. Peace is secured for the moment. But the battle for control of Demon World must begin. Who will win the tournament, and grasp complete power?