"The Duel Off, Part 1", known as "Fusion Seal! Judai VS Misawa (First Part)" in the Japanese version, is the twenty-first episode of the Yu-Gi-Oh! GX anime. it first aired in Japan on November 23, 2005 and in the United States on November 22, 2005.
At the docks, a ship is unloading at Duel Academy. A scuba diver sneaks onto the island from the ship and states he's going to uncover the school's dark secrets. Chancellor Sheppard is having a staff meeting, in which the teachers attempt to decide who will represent Duel Academy in the inter-school match against North Academy. Dr. Crowler insists that there is no reason not to have Zane Truesdale, who also attends the meeting, as their representative just as it was last year. Sheppard reveals that North Academy has chosen a first-year student, so Sheppard wishes to to choose one as well. Zane has no problem with this, and suggests Jaden Yuki for the position. Crowler does not wish for a Slifer Red student, especially Jaden, to represent them, and nominates Bastion Misawa. He suggests that the two Duel to determine who will earn the right to be their representative. The scuba diver has infiltrated the school, and enters a locker room and steals a Slifer Red jacket, intending to use it to blend in with the students. Professor Banner announces the news to Jaden and Bastion during class, and Bastion reveals that he's been building an entirely new Deck specifically to counter Jaden's Elemental HEROes, and that he's nearly finished.
The scuba diver wanders the halls, perplexed as to why Obelisk Blue and Ra Yellow students will not speak with him. Jaden meets with him, and assumes that he was held back a few years, as he appears older than a student should. Jaden drag him back to the Slifer dorm, where he rebuilds his Deck for his Duel with Bastion. He drops a "Skyscraper" card, and the diver picks it up, remembering his own past, where it appears he used an Elemental Hero Deck of his own, and suffered a loss to Seto Kaiba. He accidentally lets slip that his name is Gerard after insisting that Jaden cease calling him "old timer". He then states he doesn't like Dueling, leading them to question why he's at Duel Academy, and he says he doesn't enjoy it because he is not good at it. Chumley Huffington sympathizes with him, having been held back himself, and states that watching Jaden Duel inspired him to do better. Syrus Truesdale suggests that Gerard watch Jaden Duel, hoping this will help inspire him to become better himself. Gerard then attempts to get the information he needs out of them, and asks if they know if the rumors about disappearing students have any truth to them. Jaden asks if he means the Abandoned Dorm, which intrigues Gerard, as he hadn't heard of it. This gives him a starting point for his research, and he later ends up outside the Abandoned Dorm, where he meets Alexis Rhodes. He questions her about the missing students, but she advises him to cease his search. She departs, and he pulls out a camera, and begins to take pictures, stating that if he breaks this story, the money he gets from it could set him up for life.
At the Ra Yellow dorm, Bastion sits at his computer, still analyzing Jaden's Deck. He determines that he needs to stop Jaden from Summoning "Elemental HERO Flame Wingman" and "Elemental HERO Thunder Giant", which would mean stopping their respective Fusion Material Monsters. Racking his brains, he develops a strategy that would neutralize both threats. The next day, the whole school gathers to watch the Duel, and Gerard determines that with them distracted, this is his ideal time to act. He sneaks into the library, and begins attempting to hack into one of the school's computers. At the arena, the Duel begins, with Bastion Summoning "Carboneddon" in Defense Position. Jaden Summons "Elemental HERO Burstinatrix", using it to attack and destroy "Carboneddon" before Setting a card. Bastion draws, thinking that the card he drew is the one that will lead him to victory. He Summons "Oxygeddon" and attacks, but Jaden negates the attack by activating his face-down "Hero Barrier". Bastion Sets the card he drew and ends his turn. Jaden Summons "Elemental HERO Sparkman" and equips it with "Spark Blaster", using its effect to switch "Oxygeddon" to Defense Position. He attacks and destroys it with "Burstinatrix", which activates "Oxygeddon's" effect, dealing 800 damage to both players. Jaden attacks directly with "Sparkman", reducing Bastion to 1600 LP. This greatly worries Crowler, as he's the one who nominated Bastion for this Duel, and he appears to be losing so early on.
Turn 4: Jaden
Jaden draws "Elemental HERO Sparkman" and subsequently Normal Summons it (1600/1400) in Attack Position. He then activates "Spark Blaster" and equips it onto "Sparkman". Now during each of Jaden's Main Phases, he can switch the battle position of a monster. When this effect is used three times, "Spark Blaster" is destroyed. Jaden then activates the effect of "Spark Blaster" to switch "Oxygeddon" to Defense Position. "Burstinatrix" attacks and destroys "Oxygeddon". Since "Oxygeddon" was destroyed by a FIRE monster in battle and sent to the Graveyard, its effect activates, inflicting 800 damage to both players (Jaden: 4000 → 3200 LP, Bastion: 4000 → 3200 LP). "Sparkman" attacks directly (Bastion: 3200 → 1600 LP).
Turn 5: Bastion
Bastion draws "Hydrogeddon" and subsequently Normal Summons it (1600/1000) in Attack Position. "Hydrogeddon" attacks and destroys "Burstinatrix" (Jaden: 3200 → 2800 LP). Since "Hydrogeddon" destroyed a monster by battle and sent it to the Graveyard, its effect activates, allowing Bastion to Special Summon another "Hydrogeddon" (1600/1000) from his Deck in Attack Position.
Bastion then activates "Living Fossil" to Special Summon "Oxygeddon" from the Graveyard (1800/800) in Attack Position and equip it with "Living Fossil". Due to the effect of "Living Fossil", the effects of "Oxygeddon" are negated and it loses 1000 ATK ("Oxygeddon": 1800 → 800 ATK). Bastion's hand contains "Litmus Doom Swordsman", "Double Spell" and "Bonding - H2O". Bastion then activates "Bonding - H2O" to Tribute his three monsters and Special Summon "Water Dragon" (2800/2600) from his Deck in Attack Position.