As an attack on the Northern Water Tribe looms, Katara challenges a master Waterbender, Sokka meets a princess, and Aang takes Kuruk’s words to heart.

News of a traitor puts the trio at odds in Omashu, where a mechanist and rebels with a charming leader muddle their plans to protect the Earth Kingdom.

Aang, Katara and Sokka arrive at a small Island, home to elite warriors named after Avatar Kyoshi. The Fire Nation gets wind of the Avatar’s whereabouts.

While a new villain is under arrest at the DEO, Supergirl uses him to try and understand who is responsible for the recent attacks. Meanwhile, Andrea and Lena think back…