Sokka suffers from an illness due to his exposure to the elements during the storm. When Katara begins to contract the illness as well, Aang goes to a nearby herbalist institute in hopes of finding a cure for his friends. On his way to collect the remedy the herbalist recommends, Aang is kidnapped by a group of Fire Nation Yuu Yan archers, commanded by the newly promoted Admiral Zhao. However, a masked marauder, the titular "Blue Spirit," rescues Aang from Zhao; the "Blue Spirit" is knocked unconscious during the escape, and Aang discovers that he is Prince Zuko. Aang offers him friendship, but departs when he is rebuffed.
- Absurdly Sharp Blade: The Blue Spirit cuts through the chains and shackles holding Aang with his swords.
- Absurdly Spacious Sewer: The sewers at the fortress are huge, making it easy for the Blue Spirit and Aang to escape.
- Arrow Cam: When the Blue Spirit is struck down by the Yu Yan archer.
- Back-to-Back Badasses: Aang and the Blue Spirit protect each others backs while mowing down dozens of enemy spearsmen and archers.
- Badass Normal:
- The Blue Spirit outfights and outwits quite a few firebenders while freeing Aang, with nothing but his swords and a bucket of water.
- The Yu-Yan Archers are a ridiculously skilled group of marksmen who are able to capture the Avatar alive, without a scratch on him.
- Becoming the Mask: Aang hoped that Zuko would have become this. It didn't quite work that way.
- Bittersweet Ending: Aang is rescued from Zhao and both Sokka and Katara get better but Aang's attempt to connect with Zuko and maybe even forge a friendship fails.Sokka: Aang, how was your trip? Did you make any new friends?
Aang: No, I don't think I did.
- Blah Blah Blah: What Momo hears when Katara speaks to him.
- Brought Down to Badass: The Blue Spirit is actually Zuko, who just isn't using his firebending to avoid revealing his identity.
- Ceiling Cling: The Blue Spirit does this to evade the guard inside the fortress.
- Chirping Crickets: Done with a defrosting frog.
- Cloud Cuckoolander:
- Sokka's illness makes him more than a little loopy.
- The herbalist counts as well.Aang: You're insane, aren't you?
Herbalist: That's riiiiiiight.
- Cold Sniper: The Yu-Yan Archers: always silent, unfazed by pressure and emotion, with legendary accuracy and extremely effective.
- Combat Pragmatist: When Aang and the Blue Spirit are cornered, Zhao gives the order to his men to leave the avatar alive. Cue the Blue Spirit immediately holding his swords up to Aang's throat, effectively taking him hostage.
- Continuity Nod:
- Contrived Coincidence: Zhao receives word of his promotion to Admiral just as he's trying to recruit the Yu-Yan Archers, allowing him to make his request an order. How lucky can a guy get? Played with though, as there's no established reason why the original commanding officer of the archers should have outranked Zhao (though they may have been equally ranked). The writers could have given Zhao the authority from the beginning, simply by making the original CO someone lower ranked than Zhao. They created a contrived problem, and moments later presented a contrived solution.
- Dramatic Unmask: Aang is shocked to see Zuko beneath the mask.
- Early Installment Weirdness: This episode contains several relatively normal-looking animals, in contrast with the series' normal Mix-and-Match Critters. Miyuki is Persian-looking, Momo brings a dead mouse, and the frogs just seem to be regular frogs.
- Elite Mooks: The Yu-Yan archers. They take down the Avatar with ridiculous ease.
- Enemy Mine: Zuko helps Aang escape from Zhao so that Zuko himself can capture the Avatar.
- Face Palm: One of Iroh's opponents make this expression when he makes the move that he will win in a game of Pai Sho.
- Find the Cure!: Aang goes in search of a cure for Sokka and Kataras fever.
- I Ate WHAT?!: As their feverish delusions clear up, Sokka and Katara realize they're chewing on dethawing live frogs.
- Introverted Cat Person: The herbalist lives alone with her pet cat Miyuki after her peers left years ago.
- Insult Backfire:Aang: You're insane, aren't you?
Herbalist: That's riiight.
- Left the Background Music On: The atmospheric background music as Zuko returns to his ship turns out to be Uncle Iroh playing the tsungi horn.
- Leitmotif: Zuko's tsungi horn theme first appears here.
- Mood Whiplash: After a very intense, full of action escape, we have a very quiet, melancholic and even sad scene with Aang reminiscing after a long gone friend he had, wondering if Zuko and him could've been friends in different circumstances.
- Multishot: During their training, a Yu-Yan Archers is shown shooting four arrows at once, each of them hitting the bulls eye of a different target.
- New Era Speech: Zhao gives one to a raving crowd."This is the year Sozin's comet returns to grant us its power! This is the year the Fire Nation breaks through the walls of Ba Sing Se, and burns the city to the ground."
- Ninja: The Blue Spirit.
- Oh, Crap!: One poor group of Fire Nation soldiers sees Aang blast their companions off the next ladder, then look up to see him standing right over them.
- Pinned to the Wall: Aang is pinned down to a tree trunk by the archers' arrows.
- Rain of Arrows: Going down on Aang.
- Save the Villain: Aang rescues an unconscious Zuko from Zhao's soldiers.
- Sick Episode: Sokka is feverish and ill due to the rain. Katara later contracts his sickness. The plot revolves around Aang trying to cure them.
- Splitting the Arrow: While the Yu-Yan Archers are shown at a firing range, one of them splits an arrow, then splits that arrow, and finally the third arrow in succession, so each is embedded in the other.
- Stab the Scorpion: It looks like the Blue Spirit is about to kill enchained Aang, but then it turns out he was using his swords to cut the chains and free him instead. Plays out as a Pseudo Crisis.
- Starts Stealthily, Ends Loudly: When the sneaky escape of the Blue Spirit and Aang is foiled, they have to start an open fight with the guards.
- Talking Your Way Out: Aang tries this... unsuccessfully.Aang: Untie me, and I'll fight you right now!
Zhao: Uh... no.
- Tempting Fate: As a guard in a small lookout reads Aang's "Wanted!" Poster, he notes that the Avatar can create tornadoes and run faster than the wind. The other guard dismisses it as Fire Lord propaganda, right before seeing Aang zipping by a la Road Runner, knocking down the lookout.
- That's an Order!: Zhao gets to do this when a messenger hawk arrives just after Colonel Shinu has denied his request to use the Yu-Yan Archers.Zhao: News from Fire Lord Ozai... It appears I've been promoted to Admiral. My request is now an order.
- Two Aliases, One Character: The Blue Spirit is treated as an entirely new character until the unmasking scene.
- Underside Ride: How Zuko gets close to the fortress, getting inside the cart when the underside is checked.
- Unfamiliar Ceiling: For Zuko as he awakes under a tree after being saved by Aang.
- Villainous Rescue: Zuko kidnaps Aang from Zhao.
- Walking Spoiler: It's next to impossible to refer to the episode or the Blue Spirit himself without mentioning Zuko.