On his way to visiting his father, Brian Robeson thinks about his parents' divorce and the hatchet his mother bought him before he left. Suddenly, the pilot of the plane collapses, leaving Brian alone at 7,000 feet above the Canadian wilderness.
Brian crash lands the plane into a lake, pulls himself free, and swims to the surface. Brian realizes that when the pilot collapsed, the plane took a new course and therefore it would be difficult for the authorities to track down the plane.
Brian builds a shelter under a ledge near the lake and finds some berries to eat. The berries make him vomit for over an hour, but the next day he manages to find raspberries. He sees a bear next to the raspberry bush and runs. He stops running when he realizes the bear hadn't been there to attack him. It had only gone to eat the berries.
After a porcupine attacks Brian during the night, Brian realizes he must build a fire. Using his hatchet, he strikes the wall of his shelter to create sparks. However, he finds it difficult to turn the sparks into flames until he remembers that fire needs oxygen, and he begins to blow the sparks when they land on the fuel he has found. Finally, he produces a flame and he begins to build a fire.
The next day, Brian finds turtle eggs. He eats some of the eggs raw and stores the rest in his shelter.
Whilst out looking for material, Brian hears a plane and runs to his camp to create a smoke signal. He is too late and the plane flies away without seeing him.
Brian makes a bow and arrow good enough to catch fish. For the first time, he is confident that he can survive on the island by himself.
Brian begins to think about his future on the island and how he can survive even if he falls ill. He fortifies his shelter and builds a pen to hold a supply of fish.
A tornado hits the island and destroys a lot of his camp and tools. However, with all his new found experience and skills, Brian is able to put it all back together.
The tornado has lifted the plane's tail out of the water. It reminds Brian that there is a survival kit in that part of the plane, and he builds a raft and goes out to retrieve it.
After many problems, and much hard work, Brian returns to the camp with the survival kit. It contains a sleeping bag, pots and pans, a shotgun, matches, fishing equipment, and a transmitter.
Brian thinks the transmitter doesn't work and throws it to one side. However, he has accidentally turned it on, and a plane soon arrives to take him back home.