Long ago in an unknown ancient time, a unique child is born at the exact moment of sunrise. The heavens bestow upon the boy a rare gift: he can change his form into any dinosaur—but if he looks directly at the sun with his eyes, and if the direct light of the sun shines on him in return while in dinosaur form, he must go to the mountain where the lights touched the earth to request his return to human form, or else he will be doomed to remain that creature forever.
The child lives with his father in a small hut in the shadow of a great canyon. The mother did not survive giving birth to the child, having been mortally wounded during an encounter with an evil demon with godlike powers beyond human understanding who hates humans for possessing fire, and is thus mourned by the father in the carvings of the family’s ritual totem that stands near their hut.
As the years pass, despite the father’s grief, he still expresses feelings for his son. For although he sometimes engrosses himself in the dealings of the tribe, he still has time for the boy. When the son enters his teens, he still sees his father as wise and loving, and has himself become popular among his tribe.
Although the boy spends his days or nights traveling through the forest as various dinosaurs, he never looks directly at the sun with his eyes, and in accord with his father’s cautions, he often returns to human form an instant before he approaches human ground.
One day, however, a solar eclipse announces the return of the demon to the tribe’s canyon, and aware of the demon’s return to the canyon, fearing that the demon will attack his tribe and village, the father told his son that since the boy is the tribe’s only hope—the one light that stand against the coming darkness—he must leave the village in case the demon attacks and journey to the mountain where the lights touched the earth to seek advice from the heavens on how to vanquish the demon. The boy accepted. That night, however, a tremendous explosion silences the activities of the tribe—the demon is attacking the village! The village chief and his best warriors fought bravely against the demon, but cannot prevail against the monster’s otherworldly strange powers. The son obeys the father’s last cry to flee the hut as the demon grabs the father and silence him forever.
As he fled, however, he changes his form into a triceratops and rampages through the village to challenge the demon. Gored by the two long horns of the Triceratops, The demon heals himself with his powers, and the monster did not know of the boy’s secret ability and see only the three-horned dinosaur he has become.
He chases the boy into the forest. Cornered by the godlike monster, the boy changes into a tyrannosaurus to fight the demon, before sinking his banana-sized, dagger-like teeth into the demon, before topple a huge tree over a gorge with his tail and escape from the demon.
But the enraged demon recovers and summons the sun, and as the boy-turned-tyrannosaur was crossing over, the sun’s first rays strike him in accord with the demon’s terrible spell. The boy roars in agony and falls into the rapids below.
Gasping for breath, the boy pulls himself to shore downstream. He sees an image of himself in the water as a tyrannosaurus. Before, as a dinosaur, he could always see his human form. The revelation that he will forever remain a tyrannosaur or else go to the mountain peak where the lights touched the earth hits him hard and simultaneously inspires him. He simultaneously blames the demon for what has happened to him and swears to go to the mountain in order not only to request his human form back but also gets his revenge on the monster.
Meanwhile, ridden with guilt, the chief carves the boy’s emblem into the family totem, saying goodbye to the father and son the tribe once had. But at the same time, the chief and the shaman-woman turned to the boy-turned-tyrannosaur as the tribe’s only hope for the future.
Though he has previously changed into many dinosaurs, the boy has never really experienced their lives for long, and indeed the ways of a tyrannosaur are strange to him. As a tyrannosaurus rex, he can understand and speak to any of the saurian creatures, but he does not know what to east or where to find food.
After several days, he stumbles upon a hadrosaur carcass and discovers he has no idea how to dig into the carcass. His hunger finally drives him to sneak a morsel from a pack of raptors. The small but deadly sickle-clawed dinosaurs are about to do the boy in when a large female tyrannosaurus steps in and saves the boy. The boy slips away, but the next morning, he runs into the same T. Rex who had saved him. The humbled youth sensibly latches on to the aloof female tyrannosaur, who, though reluctant at first, finds she has a soft spot for the kid.
As the weeks pass, the adult female Tyrannosaurus teaches the youth how a T. Rex hunts and so forth. Though initially opposed, the boy begins to learn a T. Rex’s traditions and strengths. Throughout, he faces many obstacles: hunger, raptor packs, earth shifts, and the challenge of other tyrannosaurs as well as of the same demon who attacks his community. Through the strong bond he forges with his new-found friend, he learns to accept and loves his life as a tyrannosaur. And yet, this bond makes the boy still determined to achieve his quest to find the mountain where the light touches the earth and to vanquish the demon.
And so, one night, during a monstrous snowstorm, the T. Rex leads the boy and a second Tyrannosaur near a mountain. The boy recognizes where he was. He was near the very mountain where the lights touched the earth. But just then, before he can begin his perilous journey to the mountain and climb to its summit, a tremendous explosion silences the winds of the storm. The very demon who supposedly silences the boy’s father causes a nearby peak next to the mountain where the lights touched the earth to erupt (á la Mount St. Helen’s) with his strange powers, causing it to spew out billowing clouds of ash.
The boy—seeing that the demon is trying to attack his village in the valley below by destroying the mountain near his destination—rushes down the valley below to save the villagers and battle the monster.
As the boy and the demon fought, the heat from the eruption caused by the demon’s powers has loosened the snow-capped mountain next to the mountain where the lights touched the earth, the mountain next door breaking apart and avalanches toward the village. Just as the demon is about to strike the boy with his dark claws, the monster was struck by the rays of the lights that touches the earth and vaporizes into nothingness.
Just then, the powers of the lights that touches the earth envelopes the boy and levitates him to the summit of the mountain where the lights touched the earth for judgment by the spirits of his tribe’s ancestors.
Luckily, the moment he touches on the ground of the mountain’s summit, the great ancestral spirits descends upon him to reward him for his bravery and valor in the cause against the demon, and then the two adult tyrannosaurs joins the boy. The adult female tyrannosaur and her mate, to the boy’s surprise, changes into the spirits of his mother and father.
The father tells him that the precious gift the boy has was passed from father to son—they are both the same. The father tells the spirits of the tribe’s ancestors that he had not been there for the mother when she was mortally wounded by the demon and died because he had been changed because of his encounter with the godlike monster. Then the mother and father turned themselves into tyrannosaurs so not to lose their son. The boy is shocked and overwhelmed by emotions of both regret and joy.
Through his tears, the boy then asks if there is any way for him to return to his human form so that they can remain together. While the mother’s spirit looks on, the father pauses thoughtfully. When the lights that touches the earth dies down, morning light breaks over them both.
The son discovers that he is unchanged, then looks up—when they died, the father and mother has changed back into the tyrannosaurs that they were, and will be forever.