A war galley is caught in a storm at sea. The ship’s weatherworker is distressed to realize he has lost the power to control the wind and waves, but is more so when he sees two dragons fighting above the clouds, during which one is killed by the other—an unprecedented and impossible occurrence.
The King of Enlad, already troubled by tales of drought and pestilence in the land, as well as the news about people going insane, receives news both of the strange omen at sea and of the disappearance of his son, Prince Arren. The King’s wizard Root tells the tale of how dragons and men were once ”one”, until people who cherished freedom became dragons, and men chose possessions; and of his fears of how the land’s plight is because of the weakening of the world’s ”Balance”. The King has little time to ponder on this before he is fatally stabbed in a dark corridor by a young boy who is revealed to be his son Arren. The young prince steals his father’s sword and flees the palace.
Later, the Archmage Sparrowhawk (Ged) arrives at the desert, where he witnesses Arren being pursued by wolves. He rescues Arren, who later agrees to accompany Sparrowhawk on his journey and travels to the city of Hort Town, where vendors scam people and slavers sell and trade slaves. Arren, after earning a cloak from Sparrowhawk, who buys it at a cloak vendor’s stand, almost eats some Hazia from a Hazia dealer. Sparrowhawk stops him and tells him that Hazia is a drug that makes people hallucinate and then eventually die if they continue to eat it. Sparrowhawk returns to the inn while Arren goes to explore the town alone. Arren suddenly becomes scared, as if something is following him. While fleeing in fright, Arren sees a young girl with a burn scar on her face named Therru, fleeing from slavers and their leader, Hare. Although Arren saves her by fighting off the slavers, he also shocks her with his indifference to the life of any person, even his own, causing Therru to not trust him.
Later in the evening Arren falls asleep by the port and is captured by Hare and the slavers. Hare thinks Arren’s sword is worthless junk and tosses it in the sea. Arren is rescued from the slavers caravan by Sparrowhawk. Together they travel to a farm where Therru is looked after by a woman named Tenar, an old friend of Sparrowhawk. Despite Therru’s distrust towards Arren, Tenar welcomes the young prince with open arms.
Hare reports back to his master Lord Cob, an androgynous wizard, about the slaves’ escape, and almost pays with his life for the loss, until he tells Cob that it was Cob’s rival Sparrowhawk who freed the slaves. Cob orders him to bring Sparrowhawk to him at the castle. Back at the farm, Arren learns more about Sparrowhawk, Tenar and Therru’s lives. Sparrowhawk tells Arren that he is looking into the cause of the upset of the Balance. He soon leaves the farm to return to Hort Town and investigate further. While there he discovers Arren’s sword has been recovered and is on sale at a merchant’s stall. Sparrowhawk is then confronted by Hare, but transforms his face to disguise himself. When the slavers leave, he changes back and buys the sword.
Arren finds Therru singing on a hill top and reveals to her that he killed his father and that he is scared of the unknown presence following him. Seeing that Arren is more gentle then she has previously thought she begins to warm up to him. Later, afraid of the evil he could attract to the ladies’ farm, Arren leaves in secret. Tenar is captured by Hare and the slavers as bait to lure Sparrowhawk into the castle and leaves Therru behind tied to a post as a messenger. Arren is again pursued by the unknown presence, which is an exact copy of him, and runs away, stumbling into a marsh lake and falling unconscious underwater. Cob, who has been seeking Arren, saves him and brings him to the castle, where he manipulates him, saying Sparrowhawk wants to use Arren to discover the secret of eternal life. Cob blackmails Arren to reveal his ”true name”, Lebannen, to control him. Sparrowhawk, on the way back to the farm, encounters Therru, who freed herself, and gives her Arren’s sword, telling her to stay home and give it to Arren if he returns. He goes to the castle to save Tenar but instead finds Cob, whom he confronts after evading Hare and the slavers. Sparrowhawk learns that Cob is causing the world’s balance to collapse by opening the door between life and death to try and gain eternal life. After Sparrowhawk tries to warn Cob of the dangers of upsetting the Balance, Cob tells him he is ”above nature.” Cob then sends Arren out to kill Sparrowhawk, but Sparrowhawk stops him. As Sparrowhawk frees Arren from Cob’s control, he tells Arren that death is natural and that no one can live forever causing Arren to realize what he almost did. Sparrowhawk is then captured by Hare and the slavers, as his power is weakened within the stronghold of Cob’s castle. Sparrowhawk is then thrown into the same dungeon cell Tenar is locked in.
Meanwhile, Therru sees a copy of Arren and follows him to the castle, where he reveals he is the light within Arren. The reason Arren is afraid of his double is due of his fear of death and that Arren is going insane due to the darkness in his heart and due to the world’s Balance collapsing. He tells Therru his true name and says while he cannot go into the castle, he will be with her at all moments. Inside the castle, Therru learns of Sparrowhawk and Tenar’s sunrise execution by eavesdropping on Hare and the slaver’s conversation. Therru then finds Arren, full of guilt and hopelessness, and brings hope back to him by telling him that life is beautiful and that death is part of the circle of life. She then tells Arren his true name and confides in him her own true name, Tehanu. They both rush to rescue Sparrowhawk and Tenar from Cob, Hare and the slavers, who are about to execute them by throwing them off a high tower. After fighting and scaring off Hare and the slavers, Arren confronts Cob, but Cob tries to kill him with a ”Summoning Spell,” but he fights back and then finally unsheathes his sword, revealing its magical nature. Arren then cuts off Cob’s hand. With his hand and staff now gone, Cob can no longer use his magic powers. With his magic almost gone Cob begins to age rapidly and turns into a grotesque old man. He reattaches his severed hand and reveals that he wants eternal life because he doesn’t want to die and that he wants revenge on the wizards of Earthsea and Roke for banishing him for trying to control the dead and become Archmage himself. Cob then captures Therru and flees to the highest tower on the castle, with Arren in hot pursuit. Cornering Cob, Arren tries to explain what he learned about life and death from Therru and Sparrowhawk to Cob, but Cob refuses to listen and using the last of his magic, strangles Therru to death. However, she does not die as she has eternal life, and instead becomes a dragon. Therru kills Cob and rescues Arren from the collapsing castle tower that Cob destroyed on trying to prevent Arren from advancing.
Sparrowhawk and Tenar leave the castle. Tenar wonders where Arren and Therru have gone. Sparrowhawk reassures her that they have Therru’s dragon wings to guide them. Therru and Arren meanwhile land at a field where Therru changes back into a human. Arren tells Therru he will leave for home to repent for his crime, but will come back to see her some day.
In the epilogue, after Arren and Therru reunite with Sparrowhawk and Tenar, Arren and Sparrowhawk reconcile for fighting earlier. All four of them then pitch in to finish the farm chores and spend some time together like a family. Eventually, Arren and Sparrowhawk depart for Enlad, bidding Therru and Tenar goodbye. Therru then looks up to see dragons peacefully flying in the sky, indicating that the world’s balance is back to normal as the Japanese writing meaning ”The end” appears before fading to black and the end credits.