The film is set more than ten years after the plot of "Avatar" ended, telling the story of the Sully family (Jack, Neytiri and the children): the crisis has not dissipated, and the family has tried their best to protect each other, strive to survive, and go through hardships. Jack and Neytiri have formed a family, and their children have gradually grown up, bringing a lot of joy to the family. However, the crisis has not dissipated, and the Sully family has tried their best to protect each other and survive, and finally came to the island tribe near the sea of Pandora to seek shelter. The leaders of the island tribe, Tenovali and Ronar, provided shelter for the Sully family. The members of this tribe are all natural divers and have established close connections with various creatures in the ocean.