Avatar: The Last Airbender 4x01

Summary: 70 years have passed since Avatar Aang defeated Firelord Ozai and saved the world. Now, his successor, Korra, is training to be the new Avatar. After passing her firebending test, she meets with Tenzin, Aang's son who is suppose to be her Airbending Teacher. However, he tells her that her training must wait as he is still needed in Republic City. Not wanting to wait, Korra sneaks out of the South Pole and heads to Republic City where she finds herself in a little over her head.