No one had seen the innocuous rock on the long climb to the pass on the Oregon Trail, and when the last covered wagon in the long line rolled onto the lump of granite, it shouldn't have made much of a difference, but it caused almost instant tragedy. Just seconds later, the wagon plunged over the edge of the narrow trail, then began its deadly, tumbling roll into the abyss, spewing its contents as it fell to its destruction. Her precious children...