When Yugi opens a package from Duel Monsters creator, Pegasus J. Crawford, Yugi is forced to face him in the mysterious Shadow Realm where all the monsters and magic are real.

Pegasus's hired duelist Panik cheats Mai of all her star chips, and Yugi vows to defeat him and win them back. But when Panik's Castle of Dark Illusions enshrouds his monsters in a black mist, how can Yugi defeat an enemy he cannot see?

Yugi and Jonouchi pool their strengths and manage to fend off their opponents’ monsters, but things are about to change as the Labyrinth Brothers summon the almighty Gate Guardian, a monster that reflects all attacks! Is Jonouchi helping Yugi in this duel, or his lack of experience sealing their fate for defeat?