Zhao leads the Fire Nation into the North with a bold plan to weaken the Water Tribe. When the battle takes a dark turn, Aang enters a powerful state.

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.

When the group lands in the Spirit World for a rescue mission, they come face to face with dangerous threats, painful memories and a mysterious entity.