The Legend of Korra - Book 3 (Change)
Episode 1: "A Breath of Fresh Air"

Description: Two weeks after Harmonic Convergence, Korra tries to repair the damage caused by the Dark Avatar in Republic city but with no success. Meanwhile, non-benders all around the world are suddenly granted airbending abilities, which sparks hope in rebuilding the nearly nonexistent nation of the Air Nomads after one hundred years. However, a band of extremely strong and dangerous criminals are released and plot to put an end to the Avatar themselves.