The most significant consequence of Harmonic Convergence is the sudden appearance of airbending in non-bending individuals across the globe.

The Legend of Korra S3E1 "A Breath of Fresh Air" - TV Tropes

The episode introduces Zaheer , a dangerous prisoner held in a high-security White Lotus prison. Having suddenly gained airbending abilities, he uses them to overpower his guards and escape, setting out to liberate his equally dangerous associates.

, Tenzin's brother, discovers he can airbend while trying to save his spirit companion, Bum-Ju, from falling off a cliff.

The central theme of the season is established here, as the world adapts to the permanent presence of spirits and the rebirth of a long-extinct culture.

While dealing with the city's crisis, Korra and Asami spend time together, bonding over their past complicated relationships with Mako. This marks a significant shift in their dynamic from rivals to close friends.