Set against a backdrop of winter in northwest Canada during the Klondike Gold Rush of the 1890s, The Call of the Wild is the story of a dog's transformation from pet to leader of a wolf pack. The dog, Buck, has been raised as part of a human household. When he is stolen to join a sleddog pack, he is transformed into a mere servant of humans. This is a Darwinian world, where only those most fitted to the situation will survive. London describes dogfights, beatings, and Buck's growing blood lust with a lyrical touch that highlights the romantic appeal of the wilderness and wildness itself. When the traces binding Buck to the sled are cut, Buck becomes the equal of his rescuer, John Thornton, but is bound to Thornton by love. It is only with Thornton's death, when Buck kills some Yeehat Indians, that he realizes that humans have no power over him, so he turns his back on the human world to embrace the wild. Buck's adaptation is not just a matter of learning to cope with new situations, but an atavistic rekindling of wild instincts within him. In the most anthropomorphic moments of the book, Buck has visions of men in animal skins cowering by a fire in the dark. These visions make Buck's transformation seem more than just instinctive. The "call of the wild" becomes a mystical, spiritual force.