A fur trapper catches another trapper trying to steal his furs. He stops the thief, but later on the furs are stolen anyway. Rin Tin Tin Jr. tracks down the thief to try to get the furs back.

Rinnie is asked to guard the furs of his master, fur trapper Brule Conway. When Rinnie is lured away by another female dog, Conway's winter furs are stolen by Black Wolf, a henchman for the French-Canadian trapper Pepite La Joie. After a series of adventures, Rinnie masterfully captures the evil doers and returns with the furs, winning the hearts of all.—<[email protected]>