From the announcement:
The Legend of Korra, in which the mythology of the beloved animated franchise from Avatar: The Last Airbender creators Michael Dante DiMartino and Bryan Konietzko continues. The series centers around a new Avatar named Korra, a 17-year-old headstrong and rebellious girl who continually challenges and bucks tradition on her quest to become a fully realized Avatar in a world where benders are under attack. The half-hour series will debut on Saturday, April 14, at 11:00 a.m. (all times ET/PT), as part of Nickelodeon's Saturday morning block (8AM-Noon), which has been the number-one destination for Kids 2-11 for 12 consecutive years and currently delivers more than three million total viewers each week. The Legend of Korra will air regularly on Saturday at 11:00 a.m.
Everyone better be watching this!