Captain Grant Marsh ruled the Missouri River (plus the Yellowstone and Mississippi) when the steam boat was king, and continued as it began to be diminished by railroads - which later would be diminished by highways and airplanes. The book covers Marsh as he begins working as a cabin boy along the Ohio and Mississippi Rivers before the Civil War, working his way up the ranks until he is a ship's captain. Readers get a feel for steam boating, adventure, and the culture of the Native American Indians and encroaching whites in the Great plains and northwest.