Avatar: The Last Airbender Season 1 Episode 6 : Imprisoned

Aang, Katara, and Sokka camp near a small Earth Kingdom town that is controlled by the Fire Nation, which bans Earthbending. Katara convinces a young Earthbender named Haru to save an old man with Earthbending, only to have Haru captured by the soldiers. Katara devises a plan to get herself arrested so Aang and Sokka can follow her to where Haru was taken and liberate him. While at the prison, a metal sea fortress that is impervious to Earthbendi...