A new student, Ryuji Otogi, defeats Jonouchi in a game of Duel Monsters, forcing Jonouchi to become his servant. Ryuji forces Jonouchi to wear a dog costume and humiliates him in public, forcing Yugi to challenge Duke to a duel. However, this will not be a Duel Monsters duel, but a new game named Dungeon Dice Monsters!

In exchange for Jonouchi’s freedom, Yugi agrees to give up Duel Monsters forever if he loses. Unfamiliar with the rules, Yugi gets off to a rough start. His chances do not improve as Ryuji reveals that he designed Dungeon Dice Monsters with Pegasus’s aid! Can Yugi learn the new complex rules, much less form a strategy, before he is soundly defeated?

Yugi uses his innate gaming skills to turn the tables on Ryuji, but Ryuji has one more rule to mention: All creatures take up territory on the grid-like board. With no room to summon any new monsters, Yugi’s position is helpless!

After Ryuji’s all-powerful Orgoth the Relentless dices Yugi’s entire cadre of monsters into shreds, Yugi only has one turn left before he loses all his heart points! Yugi’s last hope rests in one final dice roll in the thrilling conclusion to Dungeon Dice Monsters!