The Last Airbender ending explained (spoilers)

[MatthewOvala]

Commander Zhao kills the Moon Spirit, depriving the Water Tribe of their powers. The Water Princess gives her life to the Spirit so it can live. The Water Tribe kill Commander Zhao. Katara freezes Zuko and Aang spares his life, but Zuko escapes. Aang scares off the Fire Nation by demonstrating his control over the ocean. The Water Tribe bow to Aang. The Fire Lord assigns someone else with the task of killing the Avatar and it turns out to be Zuko's sister.