Buck is a dog with a strong body and a sturdy skeleton. He used to live a pampered life in the home of the Supreme Court Justice, but was stolen by the gardener and sold to the cold Alaska, where he became a sled dog. Buck's rough fate did not end there. After that, he went through several masters who treated Buck cruelly and coldly. Not only that, Buck also experienced great challenges in order to maintain his position in the dog pack. This time, John (Harrison Ford) became Buck's new owner. Fortunately, John was a kind man. He not only treated Buck very gently, but also healed his scarred body. As time went on, a solid friendship developed between the man and the dog. However, in an accident, John was killed by the Indians. The angry Buck lost his mind and wanted to avenge his master.