The story begins in 1897, at the start of the Klondike gold rush. The discovery of gold in the Klondike—a region in northwestern Canada's Yukon Territory—prompted thousands of goldseekers to head for the far north, all of them desperately in need of dogs to pull sleds across the harsh arctic trails.

Buck, a large dog who has enjoyed a leisurely life on a California ranch, is stolen and shipped to the Yukon. Buck learns to survive in this cruel environment; he begins to discover the primitive instincts of his ancestors, and in time he responds to the call of the wild.