Tim Bannon and a young Ranger, Tate Slocum, are sent to Sierra Blanca just before Christmas to stop a budding range war before it starts. Before their assignment is completed, they will find out a range war is the least of their problems. On their way home, their train is stranded by a ferocious blizzard. On board the train is a doctor bringing badly needed smallpox vaccine to the town of Toyah. With the train hopelessly stuck, the only chance for the vaccine to reach Toyah is for Tim, Tate, and a prisoner they've captured to ride twenty miles through the teeth of the storm. That ride may just be the toughest one Tim Bannon and his horse Rowdy will ever face.