The Legend of Korra - Book 3 (Change)
Episode 5: "The Metal Clan"
Description: Team Avatar arrive in Zao Fu, a metal city led by Suyin Beifong (Anne Heche), Lin's estranged half-sister and the mother of Opal (Alyson Stoner), a new airbender. Korra begins training Opal but can't get Lin to mend the rift with her sister. In Republic City, Zaheer infiltrates Air Temple Island, but escapes after he is identified and attacked by Kya.