Today, "The Legend of Korra" Book 4 kicks off with its premiere episode, and fans can check it out online right now.

"To save the world, Avatar Korra endured her most intense battle yet. Now broken and bruised, Korra begins a journey of self-discovery and survival as the strong prey upon the weak. When an aggressive military force rises up led by the power-hungry Kuvira, the fate of the Earth Kingdom hangs in the balance and only the Avatar can set things right."

In the premiere, "It's been three years since Zaheer poisoned Korra and the members of Team Avatar have moved on with their lives; Kai and Opal help a struggling Earth Kingdom town."

The premiere episode is titled "After All These Years," and is now available on Nick.com right here.

Starting this week, "The Legend of Korra" Book 4 will also be available on iTunes on a weekly basis. To buy the HD episode, you can own it for $2.99 right here.

In addition, the episodes will also appear on Amazon, with the premiere episode already up for $2.99 in HD and also SD for $1.99. You can also purchase a season pass, which will allow you to download the episodes automatically as they come every week.