Mafatu is a boy who was afraid. He is a Tavana Nui son and his father the Great Chief of Hikueru. But when he recalled about his mother when he was a child of three he is so afraid about sea. Because there is one event was happened and cause her mother death.
Until he was young man he is so afraid to sea and villagers underestimate against Mafatu. His father ashamed to villagers because Mafatu cannot do what another young man can do whereas he is The Great Chief of Hikueru. For example, catching fish and diving to get reef.
Kana one young man of the village ask Mafatu to join them going to sea for killing a sharks and diving to get reef. However, the words would not come from his throat. He start thinking about his father, he want his father say "Here is my son Stout Heart. A brave name from a brave boy".
Finally, Mafatu succeed make a new canoe. He come back to Hikueru with a new of Mafatu. Now, he is not afraid to Moana The Sea God who always haunted he after his mother death. His father proud of Mafatu because he is not afraid to the sea and there shocked because Mafatu have necklace of boar's teeth and splendid spear flashed in his hand. At the end, Mafatu can hear his father say "Mafatu Stout Heart. A brave name for a brave boy".
Mafatu stirred and opened his eyes. He is so grateful because he was life. In the island he learned to be brave and independent. For example, he can killed wild pig, boar and shark. So many fruits in the island and that is enough in the island because he had food, fire and shelter. He wanted to make a new canoe to come back to his homeland.
Mafatu determined and bring Uri his dog into a canoe. Then paddle a canoe and drifting farther away from his homeland. He wants to prove that he can fight fears about sea to his father, stepmother, stepbrother and villagers. But in the middle of the sea he had a problem which that the sky start darkened and a lightning lit up the sea. This causes a canoe damaged.