The plot of "The Whale Rider" follows the story of a young Maori girl named Paikea Apirana, Pai for short. The story begins in the hospital the day of her birth where both her twin brother and mother have died during child birth. Her grieving father, Poro, is being pressured by his father and tribal leader, Koro, to try again for a male child as soon as possible. This is important to Koro because according to tradition leadership is handed down to the first born male child.
Poro defies this tradition in two ways. First, he refuses to accept the leadership which should traditionally be his as he is Koro's eldest son, going so far as to leave the tribe to live as an artist in Germany. Second, he does so by naming his daughter Paikea. Paikea is the name of the Maori ancestor who according to legend led his people to their current land while riding on top of a whale. Koro and all the past leaders of the tribe are direct descendants of this legendary leader. Since Pai is female she cannot traditionally inherit tribal leadership. Koro and his wife raise Pai and although it is clear he loves her, also condemns her and blames her for conflicts happening within the tribe as she is a break in traditional line to the leadership of the tribe.
To fill this gap in leadership Koro starts a cultural school for the first born village boys, hoping a new leader will emerge. He teaches the boys traditional chants and use of a taiaha, a fighting staff, which are traditionally reserved for males. Pai feels that she could become the leader and should be allowed to take part in the school; she secretly follows Koro's lessons and seeks out her uncle, Koro's second son, to teach her the use of the taiaha. When Koro finds outs his relationship with Pai further erodes. This becomes exacerbated when none of the boys succeed at the traditional task of recovering a whale tooth, the symbol of tribal leadership, which Koro had thrown into the ocean. This was the final task which would identify one of them worthy of becoming leader. Koro falls into despair with the loss of the tooth and with it no one identified to take over as leader. He calls out in chant to the ancient ones to help resolve his conflict, while unbeknownst to him Pai is calling out in chant as well from down the beach. Shortly thereafter, while on a boat outing with her uncle, Pai is told where the whale tooth had been thrown and she dive out of the boat and down to retrieve her grandfathers symbol of leadership. The family hold on to the tooth, not certain of how Koro would take to the fact that it was recovered by Pai.
In an attempt to mend the relationship with Koro, Pai invites him to be her guest of honor at a concert of Maori chants her school is putting on. During the contest it is revealed Pai had won an inter-school speech contest with a touching dedication to Koro and the traditions of the village calling out that leadership should be shared among the people thus reducing the burden on one person. Koro misses Pai's speech. He was late, and while walking to the school, he comes upon many whales which are beached near Pai's home. The entire village attempts to get them back into the water, but all efforts fail. Koro sees it as a sign of his failure and admonishes Pai against touching the largest whale because "she has done enough damage." The largest whale traditionally belongs to the legendary Paikea. When Koro and the other members of the tribe walk away in expiration and exhaustion, Pai climbs onto the back of the largest whale and coaxes it back into the ocean. The entire pod follows Pai and the large whale back into the ocean. As Pai is going out into the ocean on the back of the whale the family shows Koro the whale tooth which had been recovered by Pai. It is only then that Koro realizes he has been ignoring the true leader the entire time. Pai nearly drowns and is lost at sea for a good duration. When Pai is found and brought to the hospital, Koro asks her forgiveness and acknowledges her as his successor. The film comes to an end with the tribe, including Pai's father, uncle, and grandparents, celebrating her status as leader, as the newly finished ceremonial boat is hauled into the sea for its maiden voyage.
"The Whale Rider" is a poignant movie which entwines many themes of traditional Maori religious beliefs. There is a strong sense of the interconnectedness between the past and the future. Koro and Pai both call out to the ancient ones, their ancestral leaders, for guidance and help. While they are calling out images of whales are shown to symbolize the connection between nature and humanity. This connection is also illustrated in one scene when Pai's father comes to take her away to live with him. On the way to the airport, on a seaside highway, Pai sees the whales off in a distance swimming parallel to their vehicle. Pai interprets this as a sign from the ancestors for her to return to Koro's home and to pursue her rightful place as leader. She has her father turn around and take her back.
Another theme of traditional Maori religious belief in the movie is the legendary Paikea who is shown riding his whale in a carving which sits atop the pavilion Koro uses as the site of his school for teaching the old ways