When twenty-three-year-old John Lee learns that the Yosemite Valley Railroad is being scrapped, he yearns to save it. An ardent fanatic, John has railroading in his blood since his grandfather emigrated to the United States to work as a laborer on the first transcontinental. John arranges financing through a wealthy railroad businessman, then installs himself as general manager. In this way, he befriends Yosemite Valley's superintendent, Robinson, and the younger, quiet traffic manager, Skeeter. Together, they must make the railroad turn a profit within a year or lose their precarious financing.