At the beginning of the story, Buck experiences a carefree life in the sun-kissed Santa Clara Valley on Judge Miller's estate, where he roams freely and enjoys the relaxing environment. However, Buck is kidnapped, sold, and transported across the country, where he experiences physical abuse for the first time at the hands of a dog breaker. The dog breaker, wearing a red sweater and wielding a club, teaches Buck the important lesson to avoid any man with a club after mercilessly beating Buck into submission.
Once Buck is transported to the Northland, he experiences snow for the first time and witnesses a pack of dogs ruthlessly kill Curly when she falls to the ground. Buck begins to acknowledge the primitive, hostile environment of the Northland and learns the law of club and fang. In the threatening, dangerous environment of the Northland, Buck quickly adjusts and accepts the fact that he must adapt and transform in order to survive. Buck begins to steal food without moral consideration, learns how to run the traces, and adjusts to the competitive nature of life.
Buck eventually kills Spitz in a brutal fight, takes the lead dog position, and begins to gradually hear the call of the wild. After Buck's sled team sets records and he develops into an experienced sled dog, he narrowly survives his inept owners before John Thorton saves his life and becomes his guardian. Buck's inherent primitive nature once again beckons him into the wilderness, where he kills a moose, fights a bear, and experiences the desire to live like a wolf. Tragically, John is killed by a group of Yeehat Indians, and Buck takes revenge. After slaughtering the Indians, Buck fully embraces his primitive instincts by running with wolves and becoming leader of the pack. By the end of the story, Buck becomes known as the legendary Ghost Dog, who leads a pack of wolves and roams the wilderness as an apex predator.