Ben Carter is ordered to escort a survey party from Fort Union in New Mexico to Yosemite Valley in central California. The mission of the survey is to encourage the U.S. Congress to expand the national parks system. What should be a routine duty for the men of the Ninth Cavalry's Buffalo Soldiers is complicated beyond Ben's imaginings. In the first place, one of his men is seriously injured coming back from a scouting mission and faces a long period of convalescence. He is replaced by a new trooper who comes with a checkered background and the taint of cowardice under fire. Ben worries about the man's reliability on a mission that is being watched not just by the regimental commander, but the President of the United States. Ben learns a lot about the new man, and the people he is assigned to protect, during the long journey to California, and that his routine mission is anything but, as he discovers that the natural beauty of Yosemite covers greed and danger that rival anything he has had to face before.