John Thornton (Charlton Heston) a prospector in the 1897 Klondike Gold Rush is trying to eke out a living in the harsh conditions of the bitterly cold Yukon region of Canada, with Buck the German Shepherd dog he befriends. Thornton struggles against unscrupulous rivals and natural hazards in the extreme conditions and is greatly helped by Buck who has his own story to tell: he was abducted from a family home and taken north to become a working sled dog. Man and dog forge a true bond of friendship, working together to survive life in the treacherous frozen North. Thornton is killed by Yeehat Indians, but Buck kills the men to avenge John Thornton. At the end of the film, Buck comes to the White River to mourn the place where he died.