 Luke and Mark take a train trip to visit relatives in another town. On board the train, Luke encounters Walt, a murderer in handcuffs who is being taken by Marshal Dixon to his hanging. Walt and Luke recognize each other: Walt had once tried to kill Luke in the past, and Luke warily settles into the train seats a short distance from his old adversary. Meanwhile, Mark is fast making friends with another passenger, Nathaniel, an old man of many tales that capture Mark s rapt attention. Suddenly, the train is forced to halt: clouds of swarming grasshoppers have made the tracks impassable. While Luke investigates the stopped train, two men kill the Marshal, and free Walt, who is seriously wounded during the process. However, they take everyone in the passenger car hostage, including Mark. Luke gains access to the train compartment when Walt finds out that only Luke can apply a tourniquet to his bleeding leg. However, it s old Nathaniel who must help Luke if Walt is to be stopped and Mark and the remaining passengers saved.