Billy Silver, a young trapper, lives with his wife and little baby up in the region of the snows. Billy is energetic and finds trapping profitable. One morning while he is out examining his traps, the cabin catches fire. In the distance he hears the cries of his wife for help, and hastening to the scene as rapidly as he can make his way on snowshoes over the heaped-up drifts, he arrives just in time to save the baby and a few necessities. Their little home is burned to the ground, leaving them wholly without shelter in the cold winter time. They have no materials with which to build another house. It is too cold to take any chance on exposing the wife and baby to the extreme cold, so Billy harnesses himself to the sledge upon which he loads his family, and in due time arrives without accident at the camp of a party of surveyors, fifty miles away. Jean, the young wife, is a beauty. Billy seeks work of Lawler, the boss of the camp, but is turned down until Lawler accidentally catches a glimpse of pretty Jean. His brutal mind at once schemes out a plan, and he hires Billy to accompany a party of men about to leave for a lengthy trip. He makes the little family at home in a small cabin. Jean utilizes their pitiful few belongings to make it as homelike as possible, and they are happy with their little one for the few days intervening before the departure of Billy with the surveying party. After Billy has gone, Lawler visits the pretty young wife in her cabin. Receiving no encouragement to pursue his attentions, he goes away, but with his brutal mind still fixed upon his devilish scheme, he returns. It so happens that Billy, after going a few miles with the surveying crew, is sent back to the camp for a map, which has been left behind. His unexpected return saves pretty Jean from the consequences of Lawler's brutal passion. Billy dashes into the cabin upon hearing her cries for help and wrests Lawler from his victim. Billy does not desire to injure him, but his forbearance is a mistake. No sooner does Lawler find himself free, than he draws his revolver and tries to shoot Billy. There is a struggle for the possession of the weapon, and Lawler, his attempt to kill Billy, pulls the trigger when the revolver is pointed at his own heart, with fatal consequences to himself. Others in the camp have heard the shot and rush into the cabin. They find Billy standing with the smoking revolver in his hand. He and Jean explain, but the men, who are creatures of Lawler, notify the Northwest Mounted Police representative, and Billy is locked up on a charge of murder. Jean plans the escape of Billy from jail. The Northwest Mounted Policemen, who realize the true conditions because they arc aware of the brutal character of Lawler, have an inkling of the plan of escape, but shut their eyes to it out of sympathy for Billy and his pretty wife, and believe that he is not guilty. The plan is successful, and Billy makes his headquarters in a deserted cabin several miles away from the camp, where he continues his work of trapping until the snows of winter shall go away, and he can leave the place to join his pretty wife among friends in another country. Billy has as a pet and constant companion, a tiny white mouse, which has an inordinate and mischievous appetite for the moosehide thongs that form the network on Billy's snow shoes. The little fellow is constantly trying to eat the snow shoe strings, and Billy has considerable mending to do as a consequence. The creatures of Lawler are angry at the escape of Bill, and they incite Sergeant Brokaw, known as the "human blood hound," to pick up Billy's trail and recapture him. The sergeant finds Billy in the lonely cabin, where his sole companion is the little white mouse. There is a surprise, and Billy finds himself a prisoner with hands and feet bound with moose hide thongs. The sergeant exults in his capture and returns to where he has left his dog team for the purpose of bringing the sledge up to the cabin door, where he can load Billy upon it and take him back to jail. Billy is disconsolate. He fears the result of his trial on the charge of murder in view of the biased and false testimony which he believes will be given by the former employees of Lawler. He is despondent, but cannot do a thing with his hands and feet bound. The little white mouse comes to his aid. The little creature scents the moose hide thongs which bind the wrists of his master, and finding itself unrebuked, begins to indulge its appetite with great gusto. Its needle-like teeth quickly separate the strands and Billy is free. He hears the shouting of the sergeant outside, urging his dog team through the drifts up to the cabin, and by the time he throws the door open to carry out his prisoner, Billy springs upon him and quickly disarms the policeman. A short, quick struggle settles the affair. The police sergeant is locked within the cabin as a prisoner, and Billy escapes through the snowdrifts. Weeks of arduous adventure and hardship follow for Billy, but at last he makes his way to the distant locality, where pretty Jean and the baby are waiting for him. The little mouse also finds friends of its kind, and the last picture shows a happy family of mice in addition to Billy, Jean and the baby.