The show starts out in a way that is similar to most spin-offs within the story's continuity. It introduces the new main character while using an old character in a minor role to establish the time lapse. Korra, after an issue arises in Republic City forcing the son of Aang and Katara, Tenzin, to not be able to train Korra. Korra sneaks away with the help of Katara who takes on the role of "Gran-Gran" in this episode. Korra gets to Republic City and learns of the anti-bender unrest growing in the city. She takes up professional bending and moves in with Tenzin and his family. During the final of the Professional Bending Tournament, Amon (the bad guy) and the Equalists attack and take the bending from the other team. Korra, Tenzin and Lin Bei Fong (Toph's daughter) fight back and drive off the Equalists. Korra begins working for Tarlok in an effort to keep the Equalists from taking over the city. It is revealed that Tarlok is not only working against the greater good of the city, but is also a blood-bender. Korra is taken captive by Tarlok and attempts to contact Aang for advice. Amon finds Tarlok and Korra and Korra escapes but Tarlok's bending is taken. The equalists attack Airbender Island and Tenzin and his family escape, Lin sacrifices her bending to save Korra and the Airbenders. Korra infiltrates the Equalists and finds out that Amon's real name is Noatok (I probably spelled that wrong), he is Tarlok's brother, both Tarlok and Noatok are the son's of Yakone (the leader of a criminal syndicate in Republic City who was the first blood-bender that could blood-bend when it wasn't a full moon and he had his bending taken by Aang) AND he is a blood-bender that can use blood-bending to take other people's bending. Korra and Mako fight Amon and Korra loses her bending. The fight seems not to be going well until Amon almost takes Mako's bending and she miraculously learns to airbend. Amon gets thrown out a window and his secret is revealed to the world so he gathers Tarlok and they escape. In their escape, Tarlok blows up the boat they are on in a murder suicide. Meanwhile, Katara is unable to restore Korra's bending. She runs off and meets the spirit of Aang who restores it and gives her access to the Avatar State. She then restores the bending of everyone who lost it to Amon. The season ends with Tenzin referring to Korra as "Avatar Korra."
I give the season a 9 out of 10 because it had great art, storytelling, themes, and characters but it didn't do enough to continue the continuity to Avatar: The Last Airbender. Foremost, not once is The Mechanist mentioned. Zuko has a few passing references and Iroh has no references. Also, I don't want to rate it too high because a clip out of SDCC (San Diego Comic-Con) leads me to believe that Koh may be the main antagonist from this point on and THAT would earn a 10/10
9/10 I hope Book Two is as good