Aang encounters Roku's dragon, Fang.
"You're the spirit of this forest. Now I understand."
— Aang
Aang finds himself in a small Earth Kingdom village that is being attacked by a monster from the Spirit World. One night, this monster (named Hei Bai) captures Sokka. Aang decides to go after him. But after Aang is knocked out, he accidentally ends up in the Spirit World. There, he is told that Avatar Roku has a message for him. Aang proceeds to calm the attacking beast, restoring peace to the village. Meanwhile, Iroh gets captured by the Earth Kingdom. The soldiers who captured him wish to take him back to Ba Sing Se to face justice, the city that Iroh laid siege to for 600 days during his youth as a Fire Nation general. This causes Zuko to pause his chase for the Avatar and to instead go after Iroh.
Tropes in this episode include:
- 2D Visuals, 3D Effects: When chasing Hei Bai through the forest, Aang is reanimated in CGI.
- Aw, Look! They Really Do Love Each Other: So far, Zuko's been dead-set on capturing the Avatar and only ever acted annoyed with his uncle, but when faced with the decision between chasing Aang or saving Iroh, he chooses to help his uncle.
- Back-to-Back Badass: Zuko and Iroh before battling the five captors at the end.
- Big Damn Heroes:
- Zuko leaping into the frame and kicking a boulder aside before it can crush his uncle's hands.
- Sokka tries to do this for Aang, but gets kidnapped instead. The thought was appreciated, though.
- Bilingual Bonus: "Hei Bai" in Chinese means "Black White", matching its appearance and its title.Village Leader: He is Hei Bai— the black and white spirit.
- Dude in Distress: Hei Bai captures Sokka, who (along with other villagers that Hei Bai kidnapped) has to be freed by Aang.
- Early-Installment Weirdness: The first appearance of the Spirit World is just the normal world but with ghosts that are Invisible to Normals instead of another dimension with its own geography.
- Empathy Pet: This episode questions what Appa's true relationship with Aang is. It is just a normal A Boy and His X? Or is there a special bond, like with Roku and his dragon? Do all Avatars have this "Animal Guide"?
- Exposed to the Elements: Iroh spends the entire episode in a loincloth. Then again, he can probably keep himself warm...
- Exposition Beam: The dragon touches his tendrils to Aang's forehead, giving him visions which teach the boy about the calendar and the deadline he has to beat.
- Flash Step: While trashing the village, Hei Bai periodically vanishes and swiftly reappears elsewhere.
- Foreshadowing: Iroh is the only person who can see Roku's dragon in the Spirit World. Either he's very familiar with dragons or he's very familiar with the Spirit World.
- Friend-or-Idol Decision: Zuko has to chose between the chance to track down the Avatar, or to save his Uncle Iroh. He chooses the latter.
- Gaia's Lament: At the beginning of the episode, the Gaang come across a forest that's been burnt to the ground, and Aang laments over its destruction.
- Gaia's Vengeance: Hei Bai blames the villagers for what happened to the forest, and attack their village in retaliation.
- Hands Looking Wrong: Aang only notices he has become a spirit after gawking at his hands.
- Hero Antagonist: The Earth Kingdom soldiers who capture Iroh; from their perspective, they're bringing a dangerous war criminal to face justice.
- Hope Bringer: Once Aang realizes what Hei Bai is, he calms it down by assuring it that the forest will grow back.
- Improvised Weapon: Iroh uses his chains to fight back against the earthbenders.
- Invisible to Normals: Iroh is somehow able to see Aang riding Fang when Aang is in the Spirit World. Everyone else doesn't see or hear Aang.
- Naked People Are Funny: Iroh spends most of the episode without clothes, which is Played for Laughs.
- At the start, he bathes in a self-heated pool of water that he has turned into his own hot spring, which gets interrupted when Zuko comes to fetch him; Iroh jokingly complies, causing Zuko to have a Brain Bleach upon seeing his uncle naked.
- Later, a group of earthbenders finds him still bathing and capture him, but they wrap a Modesty Towel around him off-screen so they wouldn't "experience" what Zuko saw earlier.
- When Zuko arrives to rescue Iroh, they fight together to defeat the earthbenders, with Iroh still barely wearing anything. When the fight ends, Zuko finally snarks at him to Please Put Some Clothes On.
- Nature Spirit: Hei Bai turns out to be the spirit of the forest. The devastation done by the Fire Nation is the reason why it went on a rampage. Unfortunately, it didn't realize who was really to blame.
- No-Sell: Sokka's attack on Hei Bai goes about as well as you'd expect.
- Obfuscating Stupidity: After being captured, Iroh does his best to give the impression that he's just a kooky, harmless old man past his glory days, to make his captors lower their guard.
- One-Winged Angel: The first form of Hei Bai, when angered, is a large black-and-white creature with an extra pair of arms near its face, wearing a terrifying expression.
- Retired Badass: Where to start? There were always hints that Iroh was awesome, but this is where it first becomes clear. His nickname is 'The Dragon of the West'. He laid siege to the city of Ba Sing Se for 600 days straight. He can see the spiritual forms of Aang and the dragon when no one else can. Oh, and don't forget; this old, over-weight man can manage to escape four young and fit earthbenders, while naked and chained, all on his own.
- Rip Van Tinkle: Sokka gets trapped in the Spirit World. 24 hours later, after coming out, he desperately needs to use the bathroom.
- Scenery Censor: When Zuko ordered Iroh to get out of the hot springs, he effectively used his hand to cover his uncle's nether-regions.
- Trail of Bread Crumbs: General Iroh drops one of his slippers for Zuko to find.Zuko: [sniffs shoe] Ugh! Yep, that's Uncle Iroh.
- Two Lines, No Waiting: The A story is Aang's attempt to stop Hei Bai, while the B story is Zuko's rescue of his uncle from the Earth Kingdom troops. There's a little interaction, as Iroh can see Aang in spirit form flying on the dragon (the only person in the physical world in this episode who can), while Zuko can see Appa flying in the distance, but chooses to rescue Iroh over another attempt to catch the Avatar.
- Wham Line: The episode ends with Aang informing his friends that he has to contact Avatar Roku at a temple on a remote island. However, there are two problems: First, the contact will only work on the winter solstice, which takes place the next day. The second? The island in question is located within the Fire Nation.
- You Must Be Cold: The village elder covers Katara with a coat when she sits outside in the dark waiting for her friends to return.
