During a father-son outing, sailing along the coast of British Columbia, Angus, his father John and Yellow sail into a fierce and frightening storm. Hurricane force winds and huge waves battle the boat. Their boat is no match for the storm and a huge wave causes the boat to capsize. John is rescued quickly by the Coast Guard and brought to a hospital for recovery. Angus and Yellow are nowhere to be found.
Having sought refuge in a lifeboat, Angus and Yellow drift until they land ashore. The place seems deserted and without signs of any other people. Putting their survival skills to the ultimate test, Angus and Yellow are forced to protect themselves against packs of wolves and other wild animals, create their own shelter and send out signals for help to attract would-be rescuers. In their journey through the Canadian Wilderness of the Pacific Northwest, Angus and Yellow face hunger, severe weather from rainstorms and freezing temperatures. Their bond and trust in each other gives them the will and the means to survive. Meanwhile, desperate to find their son, Jon and Catherine, with the assistance of the Coast Guard, intensify their search for Angus and Yellow.
Eventually, rescuers find Angus, but he is forced to leave Yellow behind. Days later, while sitting on his porch, Angus blows his dog whistle. Suddenly, Yellow comes racing home.