Buck is a big-hearted canine whose blissful home life is turned the wrong way up when he's immediately uprooted from his California dwelling and transplanted to the unique wilds of the Yukon through the Gold Rush of the Eighteen Nineties. As the latest rookie on a mail supply canine sled group—and later its chief—Buck experiences the journey of a lifetime, in the end discovering his true place on the earth and turning into his personal grasp.