"A Virtual Nightmare", known as "The Unknown Challenger - The Giant Mobile Fortress Surfaces!" in the Japanese version, is the ninety-eighth episode of the Yu-Gi-Oh! second series anime. It is the season 3 premiere, as well as the beginning of the Virtual World arc. It first aired in Japan on March 12, 2002 and in the United Sates on November 1, 2003.
Before the Battle City semi-finals can commence, Seto Kaiba's blimp is suddenly commandeered by a mysterious boy named Noah, who seems to know Seto personally and reveals that he has forged an alliance with Seto's old foes, The Big Five.
The KaibaCorp blimp is en route to KaibaCorp Island (Alcatraz in the Japanese Version) when the autopilot is hacked and it suddenly changes course. A mysterious boy calling himself Noah communicates through a video message, claiming to be in control and appearing to know a lot about Kaiba despite Kaiba never having met him. The blimp docks in a fortress emerging from the ocean and is locked down by magnetic anchors.
Noah forces the gang (Kaiba, Mokuba, Yugi, Joey, Téa, Tristan, Duke and Serenity) into the fortress. There they encounter some old foes — KaibaCorp's former Board of Directors, The Big Five, who inform them that after they were defeated in Duel Monsters by Kaiba and Yugi, their bodies had been destroyed and their minds trapped in cyberspace (at the end of the Legendary Heroes mini-arc). Noah had later hacked into KaibaCorp's mainframe and uploaded The Big Five's minds into his own Virtual World so they could team up and take revenge on Kaiba.
The Big Five propose a challenge to Yugi, Kaiba and the rest of the group: a Duel Monsters tournament within the virtual world. If any of the gang loses a Duel to one of The Big Five, the winner will gain control of their body and escape to the real world while the loser's mind will be trapped in the virtual world.
For the tournament, The Big Five introduce a new set of rules where each duelist has a Deck Master. The group are briefly sent to a preview of the virtual world so they can watch a virtual Duel between a virtual duplicate of Kaiba and "Total Defense Shogun" using the Deck Master system. The Big Five explain the rule of an automatic loss if a Duelist's Deck Master is destroyed. To put the odds further in their favor, The Big Five declare that they will be Dueling everyone currently present before them; this includes non-Duelists like Tristan, Téa, and Serenity.
Featured Duel: Simulated Seto Kaiba vs. Total Defense ShogunEdit
"Blue-Eyes Ultimate Dragon" attacks directly, but "Total Defense Shogun" activates its own Deck Master ability, paying 1000 Life Points (Total Defense Shogun 4000 → 3000) to negate the attack and destroy "Blue-Eyes Ultimate Dragon".[Notes 1] Since his Deck Master was destroyed, Simulated Kaiba automatically loses the Duel.
A scene is removed in the English version near the beginning of the episode. It shows Duke and Tristan both talking about Serenity in their sleep. Joey demands to know what they're dreaming about and falls on them when the blimp jolts.
A shot of an unconscious Mai is removed from the dub.
A scene removed from the dub shows Yugi wondering about how much Kaiba hates his father.
A short scene where the underwater fortress moves over a hill is removed from the English version.
In the Japanese version, the pilot's computer screen says "Destruction System — Caution — Failsafe Warning." In the English version it is simply a giant X.
In the dub, the Big Five explain that they lost access to their bodies after spending so long in cyberspace. In the original, Kaiba says that the Big Five's bodies were left in a vegetative state after being disconnected from the virtual world. While it's never explicitly stated, both versions imply that the Big Five's bodies died after being left in a comatose state.
In the dub, the jungle scene is based on a virtual reality program that Kaiba made in his youth. In the original, it's just a large scale solid-vision program, similar to that of the duel disk.