"The Mystery Duelist, Part 1", known as "Challenge from the Past - The Terrifying Zera" in the Japanese version, is the fiftieth episode of the Yu-Gi-Oh! anime. It is the season 2 premiere, as well as the first episode in the Battle City arc. It first aired in Japan on April 10, 2001, and in the United States on November 16, 2002.
Yugi Muto now has changed his Millennium Puzzle brown rope to a chain to keep his Millennium Puzzle safe. Yami Yugi explains that this change is vital since the Millennium Puzzle connects the two and that faith has more in store. Then Yugi Muto and Téa Gardner are rushing to the soccer game when they come across a fortune teller who Yugi beileves can help him see what is in the future for him. The fortune teller asks for a personal item and suggest the Millennium Puzzle which, once in hand, he steals it. Téa runs into Yami Bakura who wants the Millennium Puzzle and uses his Millennium Ring to find the Millennium Puzzle. The fortune teller then alarms Yugi the only way to get the puzzle is to win it in a Duel. But the catch is since the Millennium Puzzle isn't close or on Yugi then he would have to do this Duel without Yami Yugi's help. During the Duel Yugi realizes that only one person has a lot of machine cards and that is Bandit Keith. His guess is right but it is not truly Keith since he is now the host of someone else, Marik Ishtar.
- Keith is under the control of Marik Ishtar, who cheats during this Duel.
- Whoever wins this Duel gets to keep the Millennium Puzzle, which Keith stole earlier disguised as a fortune teller.
- Yugi is forced to Duel without Yami Yugi. In the dub, this is because the Puzzle is not within Yugi's reach, weakening his bond with Yami Yugi. In the original, Marik staged the Duel so Yami Yugi would take over to protect Yugi, giving Marik a victory over the pharaoh as well as possession of the Puzzle. However, Yami Yugi senses the trap and holds back.
Featured Duel: Yugi Muto vs. "Bandit" Keith Howard
Turn 3: Yugi
Yugi draws. "Celtic Guardian" attacks and destroys Keith's Set monster, "Cyber Jar" (900/900). The Flip effect of "Cyber Jar" activates, destroying every monster on the field. After that happens, the Flip Effect of "Cyber Jar" lets both Yugi and Keith excavate the top five cards from their respective decks and Special Summon any Level 4 or lower monsters them drew in Attack Position or face-down Defense Position before adding the remaining cards to their respective hand. Yugi Sets a monster while Keith Special Summons "Mechanicalchaser" (1850/800) and "Ground Attacker Bugroth" (1500/1000) in Attack Position. On Yugi's End Phase, he discards four cards in his hand as his hand surpasses the hand size limit.
Turn 4: Keith
Keith draws. He then Normal Summons "Machine King" (2200/2000) in Attack Position. Due to the effect of "Maching King", it gains 100 ATK for each Machine-Type monster on the field. There are currently three ("Machine King": 2200 → 2500/2000). "Machine King" attacks and destroys Yugi's Set monster, "Silver Fang" (1200/800). On Keith's End Phase, he discards two cards as his hand surpasses the hand size limit.
Turn 6: Keith
Keith draws "Megasonic Eye" and subsequently Normal Summons it (1500/1800) in Attack Position ("Machine King": 2500 → 2600/2000). "Machine King" attacks and destroys Yugi's Set monster, "Giant Soldier of Stone" (1300/2000).
Turn 7: Yugi
Yugi draws "Curse of Dragon" and subsequently Normal Summons it (2000/1500) in Attack Position. Yugi then Normal Summons "Gaia The Fierce Knight" (2300/2100) in Attack Position. He then activates "Polymerization" to fuse "Curse of Dragon" with "Gaia The Fierce Knight" and Fusion Summon "Gaia the Dragon Champion" (2600/2100) in Attack Position. "Gaia the Dragon Champion" attacks and destroys "Mechanicalchaser" (Keith 2000 → 1250) ("Machine King": 2600 → 2500/2000).
Turn 8: Keith
Keith draws. He then switches "Megasonic Eye" and "Ground Attacker Bugroth" to Defense Position. Keith then activates "Machine Conversion Factory" to increase the ATK and DEF of every Machine-Type monster he controls by 300 ("Machine King": 2500 → 2800/2000 → 2300; "Ground Attacker Bugroth": 1500 → 1800/1000 → 1300; "Megasonic Eye": 1500 → 1800/1800 → 2100). "Machine King" attacks and destroys "Gaia the Dragon Champion" (Yugi 2000 → 1800).
Turn 9: Yugi
Yugi draws "Summoned Skull". He then activates "Makiu, the Magical Mist" to decrease the ATK and DEF every Machine-Type monster by 300 ("Machine King": 2800 → 2500/2300 → 2000; "Ground Attacker Bugroth": 1800 → 1500/1300 → 1000; "Megasonic Eye": 1800 → 1500/2100 → 1800). He then Normal Summons "Summoned Skull" (2500/1200) in Attack Position. "Summoned Skull" then gains 750 ATK due to the effect of "Makiu, the Magical Mist" ("Summoned Skull": 2500 → 3250/1200). "Summoned Skull" attacks and destroys "Machine King" (Keith 1250 → 500). On Yugi's End Phase, the effect of "Makiu" expires ("Summoned Skull": 3250 → 2500/1200).
Turn 10: Keith
Keith draws "Graceful Charity" and subsequently activates it to draw three cards and discard two cards (He illegally placed three cards on top of his Deck right before drawing through the effect of "Graceful Charity"). Keith then activates "Zera Ritual" to Tribute "Ground Attacker Bugroth" and "Megasonic Eye" in order to Ritual Summon "Zera the Mant" (2800/2300) in Attack Position. "Zera the Mant" attacks and destroys "Summoned Skull" (Yugi Muto 1800 → 1500).
- Yugi switches out the rope necklace on the puzzle for a stronger chain, fearing for its safety.
- Bandit Keith never appeared again in the regular manga, this episode was used to help with plot holes Dungeon Dice Monsters left behind as it didn't follow the manga exactly.
Differences in adaptations
- Cut from the beginning of the episode are scenes of Yugi's mother.
- All the writing on Domino City is erased from the dub.
- The words "TO BE CONTINUED" are added at the end of the dub episode.
- The gun is removed from the flashback.
- When re-aired in the 2010s, this season was titled Rulers of the Duel
- In the dub, Marik tries to force Yugi to hand over the Millennium Puzzle, in the original japanese version, Marik tries to force Yugi to reveal Yami Yugi's presence.
- After "Cyber Jar" is played face-down, it is seen face-up from behind Keith.
The following cards appeared in this episode. Cards in italics debuted here.