While Rin Tin Tin guards his fur-trapping master Brule Conway's (Grant Withers) pelts, Conway's rival, Pepite La Joie (Monte Blue), sends a henchman to distract Rinty and steal the furs out from under him. Disappointed in his dog's carelessness, Conway tries to disown him, but Rinty is determined to prove his worth and restore his good standing by tracking down the evil La Joie and recovering the furs.