Book One: Air (气) is the title of the first book of the first season of The Legend of Korra, created by Michael Dante DiMartino and Bryan Konietzko. The nomenclature refers to the Avatar Cycle: water, earth, fire, and air. The primary focus of the season is Korra's attempts to learn airbending from Tenzin while defending Republic City from the Equalist revolt, led by the masked Amon.
The season began on March 24, 2012, with the online airing of "Welcome to Republic City" and "A Leaf in the Wind", and ended at twelve episodes on June 23 of that year with "Skeletons in the Closet" and "Endgame". It was followed by Book Two: Spirits, which began airing on television in September 13, 2013.
Korra travels to Republic City to master the art of air-bending with the help of Avatar Aang's son, Tenzin.
Korra is living with her airbending teacher Tenzin on Air Temple Island. Frustrated with her inability to master airbending, she turns her attentions to Republic City's famous Pro-bending Arena. There she befriends two brothers, Mako and Bolin, who compete in professional bending matches.
Korra attempts to infiltrate the Equalist movement and learn more about its mysterious leader.
Korra is recruited to join Councilman Tarrlok's task force, which seeks to rid the city of Equalists by force.
Korra and her pro-bending teammates struggle to work together after romantic rivalries shake their foundation.
Korra and the Fire Ferrets ready themselves for the pro-bending championship as an evil threat looms over the arena.
Tensions mount when Korra begins to suspect an ally is working for the Equalists.
Korra faces off with Councilman Tarrlok as Equalist activity continues to rise in Republic City.
Korra attempts to understand her cryptic visions, while Tenzin and Beifong lead a search for Equalist hostages.
The Equalists begin their attack on Republic City.
As the war intensifies, Korra goes undercover and discovers a secret about the anti-bending revolution. Meanwhile, her teammates hunt down an Equalist stronghold.
In the season finale, Korra faces the mysterious leader of the Equalists as the war in Republic City comes to a head.