Rocky Lane's Black Jack #28

Rocky Lane must stop a smallpox outbreak threatening a frontier town by retrieving a horse that was thought to be one of two animals involved in recognizing a contaminated horse. When the deputy sheriff reveals the horse is tied at the law office, Rocky and the sheriff devise a plan to send Black Jack with a note to contact a hospital in Cheyenne for serum, realizing that Black Jack can carry the contagion and spread it if not controlled. Rocky prepares to ride Black Jack to Cheyenne to get the serum before the disease spreads through the quarantined town.