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.

In captivity, Aang meets a king with a taste for games. To find their friend, the siblings must navigate a dark tunnel — and put their differences aside.

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.

An Airbender comes to grips with his new reality as war erupts. A century later, a pair of Water Tribe siblings make a discovery that changes everything.