To "buck the sun" is to push on against the glare of sunrise or sunset. The "pushful" family at the center of this story is the Duffs, driven from the Montana bottomland to relief work on the New Deal's most audacious project - to stop the mighty Missouri with earth. "Goin' Owen," the engineer oldest son, must contend with kin as willful and unpredictable as the river itself: his twin brothers, quiet Neil and daredevil Bruce their wrathy, hard-drinking father and their mettlesome mother. Roiling these already turbulent family waters are the brothers' trio of kaleidoscopically spirited wives, a history-haunted uncle from Scotland and his unexpected bride. Around this eye-of-the-cyclone family swirls the epic that was Fort Peck and its cast of thousands - conmen and G-men, politicos and prostitutes, drawn by the workers who labored above, below and beside the river, through sweltering heat and winters so savage ice formed inside their shanties. And always, there is the river, restlessly eddying toward a tragedy that will entrap some and pardon others.