Johnny Buck is a young cowboy, working for the Bar W. In the process of roping an old stob-horned steer, Buck is thrown from his horse–and into a hidden cleft where he encounters the mystery of a murdered man and a bag of ore that just might be gold. The taciturn owner of the Bar W discounts Buck's story of the "gold," but Buck soon finds that some of the shadier ranch hands are gunning for him. With a widow's daughter, a lost mine, and a missing prospector in the balance, Buck has no choice but to solve the mystery–or die trying.