The story is set in the Yukon during the 1890s Klondike Gold Rush, when strong sled dogs were in high demand. The central character is a domesticated dog named Buck. The story starts with him living at a ranch in the Santa Clara Valley of California. Stolen from his home and sold into service as sled dog in Alaska, he progressively reverts to a wild state. In the harsh climate, Buck is forced to fight in order to dominate other dogs, so that by the end, he sheds the veneer of civilization and relies on primordial instincts and learned experience to emerge as a leader in the wild.