It tells the story of United States Army officer John Wesley Powell , who was the first to travel down the Colorado River , and the dangers that he and nine other men had to face while making a map of the region during their 1869 expedition .
It tells the real story of an officer of the United States Army called John Wesley Powell who was the first to travel up the Colorado river with other nine men to make a map of the region , and the dangers they had to face in their trip .