 Rinnie (Rin Tin Tin, Jr. is asked to guard the furs of his master, fur trapper Brule Conway (Grant Withers). When Rinnie is lured away by another female dog, Conway s winter furs are stolen by Black Wolf (Artie Ortego), a henchman for the French-Canadian trapper Pepite La Joie (Monte Blue). After a series of adventures, Rinnie masterfully captures the evil doers and returns with the furs, winning the hearts of all.