A white, teenage schoolgirl (Jenny Agutter) and her much younger brother (Luc Roeg) become stranded in the wilderness after their father (John Meillon) goes berserk. After driving them far into the Australian outback for a picnic, the father suddenly begins shooting at the children. They run behind rocks for cover, whereupon he sets the car on fire and shoots himself in the head. The girl conceals what has happened from her brother and, after grabbing some food and supplies, the pair head out into the desert.
By the middle of the next day, they are weak and the boy can barely walk. Discovering a small water hole with a fruiting tree, they spend the day playing, bathing, and resting. By the next morning, the water has dried up. They are then discovered by an Aboriginal boy (David Gulpilil). Although the girl cannot communicate with him, her brother mimes their need for water and the newcomer cheerfully shows them how to draw it from the drying bed of the oasis. The three travel together, with the Aboriginal boy sharing food he has caught hunting. The boys learn to communicate slightly using words and sign language.
While in the vicinity of a plantation, a white woman walks past the boy, who simply ignores her when she speaks to him. She appears to see the other children, but they do not see her, and they continue on their journey. The children also discover a weather balloon belonging to a nearby research team working in the desert.
After drawing markings of a modern-style house, the Aboriginal boy eventually leads them to an abandoned farm, showing the other boy a paved road nearby. The Aboriginal boy hunts down a water buffalo and is wrestling it to the ground when two white hunters appear in a truck and nearly run him over. He watches as they shoot several buffalo with a rifle, shocking him. The boy then returns to the farm, but passes by without speaking.
Later, catching the undressing girl by surprise, he initiates a mating ritual by painting markings on himself and performing a courtship dance in front of her. Although he dances outside all day and into the night until he becomes exhausted, she ignores him and tells her brother they will leave him the next day. In the morning, after they dress in their school uniforms, the brother takes her to the Aboriginal boy's body, hanging in a tree. Before leaving, the girl wipes ants from the dead boy's chest. Hiking up the road, the siblings find a nearly deserted mining town. A surly white man who directs them towards a nearby hotel.
Years later, a businessman arrives home as the now grown-up girl prepares dinner; while he embraces her and relates office gossip, she imagines a scene in which she, her brother, and the Aboriginal boy are playing and swimming naked in a deep pool in the outback.
What does the children discover?
weather balloon