While on a canoe trip in the Canadian Rockies, trapper André Dupas, his Malemute pup, Nikki, and an adopted bear cub, Neewa, are capsized in rough water. André struggles ashore, but the two animals, tied together by a leash, are pulled downstream. When they reach land they are forced to overcome the instinct that makes them natural enemies and join together in a search for food and shelter. Despite many fights, they eventually become friends and remain together even after their leash breaks. With the coming of winter Neewa goes into hibernation and Nikki wanders off alone. He steals the bait from traps until he is captured by a vicious trapper, Jacques Lebeau, and Lebeau's reluctant Indian companion, Makoki. After watching the now full-grown dog kill a wolf in spite of the trap, Lebeau decides to train Nikki as a fighting dog although pit-fighting is illegal. When André, the new factor, challenges Lebeau for breaking the law, he is pushed into the pit with the brutalized killer dog. Nikki recognizes his old master, however, and joins André in fighting Lebeau, who is accidentally killed with his own knife. Later, while on a trip to André's trap line, Nikki spots his old friend, Neewa; but the dog realizes that the full-grown bear is happier roaming the wilds, and he chooses to remain by André's side.