This episode is part of the Avatar Book One - Water
Avatar The Last Airbender Episode Guide ~ via Wiki
Finally reaching the North Pole, Aang finds a Waterbending Master. However, the Master refuses to teach Katara because she is a girl. Meanwhile, Sokka spends time with Yue, Princess of the Northern Water Tribe. Admiral Zhao hires the pirates (from The Waterbending Scroll) to assassinate Zuko while he prepares a massive fleet to invade the North Pole.