Billy McVeigh, a member of the Royal Northwest Mounted Police, runs amuck another person of this service undeserving of its uniform, named Nome. The latter becomes his sworn enemy and is alert for a chance to "get even." A mysterious murder is committed in the forest far to the north of the barracks, and Scottie Deane is reported to have committed same. Billy and Nome are selected to make the arrest, and the instructions are that Billy take the trail in one direction and Nome in another, the two converging later on. So they leave headquarters, the two enemies on their long, lonely and perilous mission. Some time later, as Billy battles his way through a snowstorm, he meets a young woman urging along a dog team almost exhausted. On the sled is a long box like a rude coffin. His inquiries elicit from her the story that she is taking the body of her dead brother to the settlement. The warmhearted Billy, deeply moved, decides to accompany her, and they camp for the night. He sets up a tent for her and one for himself. During the night she slips into his tent, takes his rifle, goes to the apparent coffin, opens it, and liberates a live man, her husband, Scottie Deane, the man wanted. Scottie, however, is not a criminal, as he slew the other man in self-defense. Scottie's wife, Isobel, in extenuation, pins a note to Billy's tent explaining this, asking forgiveness for her seeming ingratitude and asking him not to follow them for her sake. Nome and another constable, Carter, happen across Billy's camp the next morning. Billy seeing his enemy, instinctively reaches for his gun, and then realizes that it is gone. Nome grows suspicious, and begins to question Billy concerning the two tents. Billy then tells the latter that a half-breed spent the night with him, but Nome, still suspicious, investigates the second tent and confronts Billy with some strands of golden hair from Isobel's head. Billy takes it from him, and makes as if to throw it in the fire, but really keeps it as a sacred souvenir. Nome and Carter laugh at his inability to explain away the hair, and tell Billy that after they have rested they intend to trail his "half-breed." They then retire to the second tent. Billy now realize that the only way to save Isobel, with whom he is deeply smitten, is to rush on ahead and arrest Scottie himself. He appropriates the sleeping policeman's gun and sets out on his snowshoes to overtake the fugitives. He is a skilled trailer, and he soon overtakes Scottie and Isobel in their camp and overpowers the former. Isobel turns furiously on Billy. At this moment Nome and Carter appear. Nome denounces Billy, coarsely accuses the girl most unjustly, and a stand-off fight ensues, in which Carter and Nome are driven off. Billy then explains to Isobel why he arrested Scottie, liberates his prisoner and bids them good-bye. When Nome's report reaches headquarters, Billy is dismissed from service and he becomes a hunter in the solitudes. Scottie and his wife return to the wilds. He goes to a distant place to get their little daughter, who was placed in charge of a French family when they made their original flight. While he is there, the house is attacked by Indians, and all the whites are on the verge of being wiped out when Billy comes to the rescue. He finds Scottie dying, but Billy recognizes him as he enters the room, and he places his little girl (Isobel) into Billy's keeping, begging him to restore her to her mother (of that dear name) in the far forest home. Billy regards this trust as sacred, and they make the long trip to find the mother down with the smallpox, and deserted even by her Indian servants. He gets help from a missionary, and Billy having obeyed the request of the dying man, resumes his wanderings. Some months later he receives a letter from the missionary, telling him that the mother and child were saved. Learning that little Isobel is in Montreal, and seized with a longing to see her again, he goes to the big city, finds the little girl and meets the mother once again. Eventually both the Isobels, mother and daughter, become the members of his own family.