When Caryl (Lois Wilde) tries to put an end to embezzlement within her company by sending stolen bank bonds to her fur-trapping uncle, the uncle soon turns up dead -- a victim of foul play. Enter Royal Canadian Mountie Sgt. Brad Sheridan (Ralph Bushman) and his dog, Rin Tin Tin, who have come to investigate the situation and rescue Caryl from the criminals, with Rin Tin Tin never ceasing to amaze humans with his cunning detective work.