George is a man who inherits a valuable family heirloom. On her death bed, his aunt begged him to always take care of the diamond, but his cousin Henry is jealous. When George sets out for the gold fields of the Yukon, Henry follows him there looking for revenge. Secretly watching their camp, Sgt Preston and his dog, King see a potential danger when Henry shows off his prowess with a knife. Later, while George sleeps, King is the only one to see the theft of the diamond, and springs into action. King is also the only one who knows what happened in the struggle with Henry, and how he came to the justice he deserved.