Reddit reviews The Legend of Korra Book 1

It's not impossible.

http://www.amazon.com/Welcome-to-Republic-City/dp/B007QYRCX6/ref=sr_1_1?s=instant-video&ie=UTF8&qid=1420729014&sr=1-1&keywords=the+legend+of+korra

100% legal, and 100% available right now. Pricey? Yes.

Ooooh you're uninitiated! Okay, you're going to want to start with Avatar: The Last Airbender. Then when you're finished, start the spinoff series, The Legend of Korra.

Trust me.

Book 1 and 2 are free to watch if you have amazon prime.

The sequel series The Legend of Korra is also available.

Amazon Prime | iTunes | Google Play

The whole show or this season? I don't think Nick has the whole show up on their site now. You'll have to pirate it or get it somewhere like Amazon. Book 3 is below.

1 "A Breath of Fresh Air"
2 "Rebirth"
3 "The Earth Queen"
4 "In Harm's Way"
5 "The Metal Clan"
6 "Old Wounds"
7 "Original Airbenders"
8 "The Terror Within"
9 "The Stakeout"
10 "Long Live the Queen"
11 "The Ultimatum"
12 and 13 "Enter the Void" and "Venom of the Red Lotus"