S1E18 · Book One: Water - Chapter Eighteen: The Waterbending Master

Complete story — includes the ending

The group finally reaches the Northern Water Tribe, where they receive a hero's welcome. Sokka meets Princess Yue, the daughter of the chief, and is immediately attracted to her. Aang and Katara seek to learn waterbending from a rather snippy master named Pakku, but he refuses to teach Katara, as women in the Northern Water Tribe are only trained to use their waterbending for healing, with combat training reserved for men. Sokka tries to spend more time with Princess Yue, who agrees to meet him later on that night. However, when the time comes Yue changes her mind and runs away. Meanwhile, Zhao commandeers Zuko's crew for a mission to attack the North Pole, and in the process deduces that Zuko is the Blue Spirit who freed the Avatar. Katara, inspired by a comment from Sokka, suggests that Aang teach her what he learns from Master Pakku every night. Unfortunately, Pakku is onto them and discovers them, and refuses to teach Aang any further. In front of the tribe council, a fed-up Katara refuses to apologize to Pakku so he may change his mind and instead challenges him to a duel, demonstrating her considerable skill and potential. Zhao hires the pirates from "The Waterbending Scroll" to kill Zuko, which they attempt by blowing up his docked ship while Iroh is out for a walk. Back at the Fire Nation port, Zhao blatantly feigns remorse to Iroh and offers the former general a place beside him for the mission. Iroh accepts, but is revealed to be deceiving Zhao by helping Zuko fake his own death and stow away as a soldier aboard the command ship. Back at the North Pole, Pakku takes notice of Katara's pendant, given to her by her mother and her grandmother before her, and realizes that Katara's Gran-Gran is his ex-fiancée Kanna, who also could not tolerate the Northern Water Tribe's customs and left to start a new life with the Southern Tribe. Sokka proceeds to tell Yue how he feels about her, which culminates in Yue kissing him. She sadly tells Sokka that she also has feelings for him, but they can't be together since Yue is engaged to be married. As a new day dawns, Pakku has agreed to train both Aang and Katara while Zhao's massive armada departs for the North Pole.