-->"Bumi, you're a mad genius."

As the gang continues on their journey to the North Pole, they stop at the city Omashu, a place Aang remembers from his child-hood for his friend Bumi and its elaborate earth-bending controlled mail system. The group takes advantage of said mail system for fun, but their antics create massive property damage, leading to them being captured by the Royal Guard. The slightly insane [[TitleDrop King of Omashu]] realises that Aang is the Avatar, and imprisons Katara and Sokka in living crystal; if Aang wants to free them, he shall have to complete three tasks.

The first test is to fetch a key (For the king's lunchbox, apparently). Problem is, the key is kept in the center of a downpour of water above a pit of stalagmites. The pressure too great to just climb up the ladder, Aang is able to get the key by flinging a stalactite at it, knocking it out of the water and over the king's head.

The second test is to fetch the king's pet, Flopsy. Aang is led to a pit where a small bunny is kept...and a giant gorilla-goat! After some comic chasing, Aang realizes that the goat-rilla is Flopsy, who acts very docile when called for.

The third test is a duel. Two fierce-looking warriors come out, and the king tells Aang to choose his opponent. Trying to be clever, Aang tries to TakeAThirdOption and challenge...the king! Too bad the king has some ''serious'' muscle underneath all those robes and wrinkles!

->'''King:''' You thought I was a frail old man, but I'm the most powerful earthbender you'll ever see!

The duel starts off badly for Aang, who continually has to avoid the king's mighty earthbending. The king for his part mocks Aang use of traditional airbender tactics of evasion, goading the Avatar to be more creative. Aang eventually tries to use his airbending to redirect the king's earthbended boulders, becoming more offensive culminating in a self-made ''tornado.'' The king soon calls the duel off and congratulates Aang for his fighting spirit, but tells that the Avatar has one more challenge (After all, what good are tests if you don't learn anything?); What is the king's name?

Aang confers with his Water Tribe comrades, and after dismissing Sokka's suggestion wonders about the previous tests. To pass all of them, Aang had to open his mind to all of the possibilties...Aang realizes what the king's name is. Confronting the leader of Omashu, Aang goes up to him and...gives him a big hug.

->'''Aang:''' You're a mad genius, Bumi.

The two friends reunited, Bumi removes Katara and Sokka's crystal capsules. He also reveals why he tested Aang; First off, [[ItAmusedMe it's fun]]. Second, in order to defeat Fire Lord Ozai and restore balance to the world, Aang will also have to think like a mad genius. The episode ends with Aang and Bumi playing with the city's mail system, at the expense of a certain merchant of cabbage...

!!Tropes
* AirVentPassageway: ZigZagged. Aang suggests escaping through the air vents, but [[SubvertedTrope Sokka notes that they couldn't fit]]. Aang says that even though they can't fit, [[DoubleSubversion Momo can]]. However, Momo just [[ZigZaggingTrope gets stuck halfway through the air vent hole]].
* ArsonMurderAndJaywalking: The Gaang are hauled up in front of the King for "vandalism, traveling under false pretenses and malicious destruction of cabbages."
* ChirpingCrickets: Some guy coughing.
* CrouchingMoronHiddenBadass: Bumi
* DishingOutDirt: Hey, King Bumi's an Earthbender, its his thing.
* FluffyTamer: King Bumi.
* FluffyTheTerrible: "Flopsy" turns out to be the hulking gorilla-goat, not the little cute pet. Though it winds up being just as docile as you'd expect something named "Flopsy" to be.
* FruitCart: The Cabbage Merchant and his cabbages.
* GenreSavvy: King Bumi almost certainly anticipated that Aang would pick a weak looking opponent for the third test, so he included himself in the selection.
* GildedCage: The heroes' prison cell was newly refurbished and looked like a nice hotel room.
* HiddenPurposeTest: The King was Bumi, and the tasks were partly a test to see if Aang could think creatively.
* MadEye: Bumi
* NoKillLikeOverkill: Okay, so those cabbages couldn't come into the city, but did the guards need to catapult them into a ravine?
* NoMrBondIExpectYouToDine: When the protagonists are arrested, the king proclaims their sentence: "THROW THEM... a feast!"
* OffWithHisHead: The cabbage merchent suggests this punishment.
-->'''Cabbage Merchant:''' Off with their heads! One for each head of cabbage!
* OhCrap: Aang, when he finds out that King Bumi isn't a wimpy-looking old man, but is in fact one of the most powerful Earthbenders on the planet.
* OverlyLongName: Aang initially identifies himself as "Bonzu Pipinpadaloxicopolis III".
* {{Pun}}: Quite a few, thanks to King Bumi.
* RecurringExtra: The poor cabbage merchant's first appearance.
* TakeAThirdOption: When presented with a choice of warriors to fight, Aang chooses Bumi instead. Subverted when Bumi turns out to be even stronger than the scary-looking guys, and he all but calls out Aang for taking the predictable out.
* UnpronounceableAlias: See OverlyLongName above. Though Katara and Bumi can keep up with it just fine.
* WhamLine: When Aang chooses the King as his opponent. Doubles as a [[PreAssKickingOneLiner Pre-Asskicking One-Liner]].
-->'''[[CrouchingMoronHiddenBadass King]]:''' Wrong choice.
* TheWindowOrTheStairs: The titular King is putting Aang through a series of tests. For the last one, he tells Aang to choose a warrior to fight. Aang tries to TakeAThirdOption and choose the old, crazy King himself - but he was expecting this, informing Aang that he's an incredibly powerful earthbender and tougher opponent than any of the warriors presented. In fact, he's the strongest in the entire series until Toph comes along, and even then it's debatable.
-->'''His Majesty:''' Heh heh, ''wrong'' choice!