Maui, the shapeshifting demigod and master of sailing, steals the heart to give humanity the power of creation. However, Te Fiti disintegrates, and Maui is attacked by Te Kā, a volcanic demon, losing both his magical giant fishhook and the heart to the depths.
A millennium later, Moana, daughter of Motunui’s chief Tui, is chosen by the ocean to return the heart to Te Fiti. However, Tui arrives and takes Moana away, causing her to lose the heart. Tui and Moana’s mother Sina try to keep her away from the ocean to prepare for her ascension as the island’s chief. Years later, after Moana has grown older, a blight strikes the island, rotting the coconuts and dwindling the number of fish caught. Moana suggests going beyond the island’s reef to find more fish, but Tui forbids it. Sina explains to Moana that Tui and his best friend tried going beyond the reef, but the latter perished. Moana and her pet pig Pua try conquering the reef but are overpowered by the ocean’s tides and end up shipwrecked back on Motunui.
Moana’s grandmother Tala shows her a secret cave, where a number of ships are hidden, revealing to Moana that their people used to be voyagers. Tala explains they stopped when Maui stole Te Fiti’s heart and that Te Kā’s darkness is poisoning the island, but it can be cured if Moana and Maui return the heart to Te Fiti, which she gives to Moana. Tala falls ill shortly after and dies, but not before encouraging Moana to go and fulfil her destiny.
Moana sets sail on a drua found in the cavern, accidentally accompanied by her dim-witted rooster Heihei. Moana is caught in a typhoon and shipwrecked on an island where she finds the stranded Maui, who traps her and steals the camakau, but Moana catches up to him with help from the ocean. She demands that Maui return the heart but he refuses. Maui is accompanied by a sentient “Mini-Maui” tattoo, acting as his conscience.