On May 14, 1804 Captain Meriwether Lewis and William Clark left the docks in St. Louis, leading a secret expedition up the Missouri River with the goal of finding a passage to the west coast of the continent. A young blacksmith's apprentice, Hugh McNeal, begs for and gains a last minute spot on the company's roster. As they travel up river, the company experiences hardship, sickness and the dangers involved with meeting the primitive natives that inhabit the banks of the Missouri. But the promiscuous nature of the Indian women they meet proves a distraction from the men's daily tribulations. A light-skinned, red-haired child is born of a liaison between Hugh and a young Dakotah girl, Bright Morning. It is a difficult birthing aided by the girl's medicine god and mystical dreams. Fearing that the child's medicine is strong, the young girl's husband changes her name to Horse Woman and names the baby Horse Woman's Child.