Mase Campbell has earned a reputation as a skilled wagon master, heading up freight trains for Kavanaugh Freight. Then one night in 1874 in Corinne, Utah Territory, he is stopped in the street by someone asking him for a match, and shot to death. Those who saw the murder either do not come forward or admit no knowledge. Buck McCready, captured at ten years of age by Indians, rescued by Mase, and raised by him, wants to find out who killed Mase and why. But there is not time for investigation because Jock Kavanaugh, owner of the freight line, has committed to a freight wagon race from Corinne to Virginia City and he needs Buck to replace Mase as wagon master. Buck believes that Mase was murdered because of the competition and that the murderer will probably be on the train. Buck is right about one thing: someone in the wagon crew is willing to do whatever is necessary to see the Kavanaugh venture fail.