When Jaden is blamed for beaning Crowler with a tennis ball, his punishment is to take extra tennis lessons - unfortunately, the guy teaching him is the worst. Harrington is the type of obnoxious, snobbish Obelisk student who gives honest, hard-working Obelisks a bad name. And when he sees Alexis, he falls in love, although the feeling clearly isn't mutual.
When Alexis tries talking to Jaden (about Chaz's whereabouts), Harrington suddenly gets jealous, and sees Jaden as a competitor. He challenges Jaden to a duel with incredible stakes - the winner gets to be Alexis's fiance! Jaden is a little confused, but he never turns down a challenge.
Harrington starts by playing a Spell Card called Service Ace (not a real card; in fact, almost all of his cards are made up). This lets him choose a card from his hand, and Jaden has to guess if it's a Monster, Spell, or Trap; if he guesses wrong, he loses 1,500 Life Points. Jaden first guesses Spell... Harrington asks if he's sure... Jaden changes his mind, and says Trap. But it's neither, it's a Monster called Mega Thunderball. (Jaden: 2,500). Harrington says it's fifteen-love. (He also has to remove the Mega Thunderball from play.) Harrington places a card facedown and ends his turn.
Jaden's turn. He summons Elemental Hero Avian in Attack Mode (1,000/1,000). He tries to make a direct attack (not the brightest move, if you ask me), but Harrington has a Trap ready - Recieve Ace. It negates Avian's attack and deals another 1,500 points of damage to Jaden. Harrington then has to discard the top three cards from his deck to pay the cost of the Trap. (Jaden: 1,000) Harrington says it's thirty-love. Jaden sets a card facedown and ends his turn.
Harrington tries to finish Jaden off with another Spell called Smash Ace. He gets to draw a card, and if it's a Monster, Jaden loses another 1,500 Life Points. He draws, and it's a Monster called Mystical Shine Ball. Fortunately, Jaden has a Trap of his own - Feather Wind, which negates a Spell Card so long as Avian is on his side of the field.
After insulting each other, Jaden moves. He plays Polymerization to fuse Elemental Hero Clayman and Elemental Hero Burstinatrix into Elemental Hero Rampart Blaster! (2,000/2,500) He attacks Harrington directly with both his monsters! (Harrington: 1,000)
Harrington plays a powerful Spell Card called Deuce. It can only be played when both duelists' Life Points are tied at 1,000, and it has has multiple effects: first, each duelist can only attack with one monster during their turn. Second, Life Points no longer matter: whoever damages their opponent twice in a row wins.
Then Harrington summons a monster called The Big Server (this creature appears to be a Machine of some sort). It only has 300 ATK, but it can bypass Jaden's monsters and attack directly, which is just what it does. Also, because it succeeded in attacking, Harrington is able to take another Service Ace from his deck and use it. He also has to let Jaden draw one card, but he says it won't matter, because nothing he can draw could be as good.
Again, he tells Jaden to guess what kind of card he's holding, and if Jaden guesses wrong, that will be two hits in a row! (We can see that it's another Mega Thunderball.) Jaden guesses Monster this time; Harrington is surprised that he got it right.
Harrington ends his turn by Equipping The Big Server with Giant Racket. A Monster Equipped with this card can negate one attack against it.
Jaden draws. He plays De-Fusion to split Rampart Blaster back into Clayman and Burstinatrix. He says that now that he has three monsters, even if his first attack is blocked, he can attack with two more.
Harrington laughs and says that now he knows why Jaden is a Slifer - he doesn't listen. With Deuce active, he can only attack with one monster. But Jaden says that now HE knows why Harrington is a snobby Obelisk - because he underestimates his opponents!
Jaden plays a Spell Card called Feather Shot. He tells Harrington that he drew the card due to The Big Server's effect, when Harrington says it didn't matter... But it does matter, because now Avian can attack once for every monster Jaden has on the field! he attacks once, and Giant Racket deflects it; he attacks again, and The Big Server is destroyed; he attacks directly, that's two in a row, and he wins.
Harrington runs off crying. Jaden tells Alexis he guesses he's her fiance... and then he asks what a fiance is. Alexis sighs, and says it's a friend... for now.