YUGI and his friends are in awe over GRANDPA's collection of DUEL MONSTERS cards, but when #1 ranked Duelist and ruthless tycoon KAIBA kidnaps GRANDPA to get the rare BLUE EYES WHITE DRAGON card, YUGI must face KAIBA in the ultimate DUEL MONSTERS showdown and avenge his Gramps!

YUGI and friends take a break from honing their card playing skills to watch WEEVIL and REX RAPTOR compete in the DUEL MONSTERS Regional Championship. When YUGI opens a package from DUEL MONSTERS creator, MAXIMILLION PEGASUS, YUGI is forced to face him in the mysterious SHADOW REALM, where all the monsters and magic are real. YUGI loses, and PEGASUS claims GRANDPA's soul as his prize. YUGI must travel to the DUELIST KINGDOM and win PEGASUS's tournament if he is ever to see his GRANDPA again!

YUGI gives up one of his own star chips so JOEY can board the boat bound for DUELIST KINGDOM and duel to save his sister's eyesight. Meanwhile, TEA and TRISTAN stowaway to join their friends. But when word spreads that YUGI was the one who defeated World Champion KAIBA, the cheat WEEVIL tries to cripple YUGI's deck by tossing his best cards overboard just as they reach the island!

Once YUGI and his friends reach Duelist Kingdom, PEGASUS announces that there are many strange secrets on the island which will make his ultimate tournament unlike any they've ever had. But when WEEVIL begins to use these mysterious new rules against YUGI in a duel, YUGI must not only figure the rules out, but master them if he's to survive!

After YUGI defeats WEEVIL's first wave of Duel Monsters, he's shocked to discover that WEEVIL has one last trick up his sleeve; a ravenous GREAT MOTH that grows in power with every turn! Can YUGI find a way to destroy this winged beast before it destroys him?

JOEY searches for a dueling opponent he stands a chance of beating when he finds himself courageously accepting a challenge from veteran duelist, MAI. But when MAI begins to demonstrate an unnerving psychic-like ability, JOEY becomes totally flustered, leaving him no choice but to figure out MAI's secret strategy before falling victim to it!