Avatar: The Way of Water

Sixteen years after the Na'vi repelled the Resources Development Administration (RDA) from Pandora, Jake Sully is chief of the Omatikaya clan. He and his wife Neytiri have two sons, Neteyam and Lo'ak, a daughter, Tuktirey ("Tuk"), and an adopted daughter, Kiri, who was born from the inert avatar of Dr. Grace Augustine. Miles "Spider" Socorro, son of the deceased Colonel Miles Quaritch, is a close friend of the Sully children, and is being raised by the human scientists who stayed on Pandora.
The RDA returns to colonize Pandora. Among the colonists are recombinants, Na'vi avatars implanted with memories of dead human soldiers, including a recombinant Quaritch. As Jake leads a guerrilla warfare campaign against the RDA, Quaritch searches for Jake's headquarters. Quaritch and his team capture Jake's children, but Jake and Neytiri free them. Quaritch also captures Spider, and recognizes him as his son. After the RDA fails to gain information from Spider, Quaritch decides to spend time with his son to gain his favor. In return, Spider teaches Quaritch about Na'vi culture and language.
Knowing that Spider's knowledge could lead Quaritch to the Omatikaya, Jake and his family leave their clan and relocate to Pandora's eastern sea, where they are granted asylum by the aquatic Metkayina clan. The Sully family begins assimilating into the clan by learning their ways, although Jake's children have conflicts with the sons of Tonowari, the Metkayina chief. Lo'ak befriends Tsireya, Tonowari's daughter.
Tonowari's son Aonung and his friends entice Lo'ak to join a hunting trip, but strand him in a dangerous part of the sea. Lo'ak is saved from a shark-like predator by Payakan, who is a Tulkun—a highly intelligent whale-like creature. Lo'ak bonds with Payakan, and learns that he has been exiled by the other Tulkun. Kiri connects to the Metkayina's underwater Spirit Tree and meets her mother Grace in a vision, but suffers a seizure and nearly drowns. Jake summons his scientist friends Norm Spellman and Max Patel for help; they diagnose Kiri with epilepsy, warning that she may die if she links with the Spirit Tree again.
Quaritch tracks Norm and Max's aircraft to the Metkayina's archipelago. He commandeers a ship which is hunting the Tulkun, and interrogates the Na'vi in the archipelago. After the Na'vi fail to give him information about Jake, he burns their dwellings. Meanwhile, Lo'ak mentally links with Payakan and learns that he was exiled because he attacked humans who killed his mother, a violation of the Tulkun vow of pacifism.
Aware that the Metkayina have a spiritual bond with the Tulkun, Quaritch attempts to draw Jake out by ordering the ship's captain to hunt Tulkun close to Na'vi villages. When the Metkayina learn of the Tulkun killings, Lo'ak goes to warn Payakan, accompanied by several other children. They find that Payakan has been tagged for capture by the RDA. They help him escape, but are caught by Quaritch's team. Jake, Neytiri, and the Metkayina pursue Quaritch, who demands that Jake surrender himself in exchange for his children. Before Jake reaches the ship, Payakan attacks it, sparking a battle between the Metkayina and Quaritch's forces. Spider sabotages the RDA vessel, while Neteyam rescues Lo'ak, Tsireya, and Spider. During their escape, Neteyam is fatally shot.
Enraged at Neteyam's death, Jake and Neytiri attack Quaritch's crew, seeking to rescue Kiri and Tuk. After Jake frees Tuk, Quaritch threatens to kill Kiri, but he releases her when Neytiri threatens to kill Spider. After a tense skirmish, Jake strangles Quaritch unconscious. Jake is rescued from the sinking ship by Lo'ak and Payakan, while Kiri saves Neytiri and Tuk. Spider saves Quaritch from drowning but refuses to stay with him.
After Neteyam's funeral, Jake informs Tonowari of his decision to leave the Metkayina, but Tonowari declares Jake's family part of the clan and welcomes them to stay. Jake realizes he cannot keep running from Quaritch and the RDA, and must stand and fight instead.