In November of 1819, eleven-year-old Sean O'Malley sets out on a fateful hunt with his grandfather. In a violent storm, Sean fires at what he believes to be a deer, but what turns out to be a young Indian warrior on a vision quest. Sean's grandfather says there is nothing they can do for the dying boy and takes the young warrior's Spirit Bow. Grandpa then tells his grandson, "Nice Shot." These simple words will haunt Sean for years to come. The young warrior's death sets in motion, a series of tragic consequences that will have a lasting effect on young O'Malley.
The dead warrior's tribe kills Sean's family in retribution and kidnaps his little sister, Becky. In their grief, Sean and his father, Patrick, sell the family farm and head out to make a new life in Oregon Country. In St. Louis they cross paths with Hatchet Jack, Patrick's estranged half brother. Sean wants to warn his father not to trust Jack, but he has not yet regained his ability to speak after the tragedy.
Patrick and Sean set out with Jack and Chimalis, Jack's captive squaw. Sean and Chimalis become fast friends, and she begins teaching him her native Crow language. One night on the journey, Jack wakes Sean to tell him that Patrick has been killed by Indians. Sean won't learn the truth of it for another year—that Jack killed Patrick in a drunken, jealous rage. Jack buries his half brother, then leads them out on the trail to a cabin where they will trap and wait out the winter. Sean proves his worth as a hunter, but Jack's approval is fleeting. The colder it gets, the more Jack sinks into drunken lunacy. His abuse of Chimalis grows more violent by the day, and he takes to beating Sean as well. One night they fight back. In the struggle, the cabin catches fire and Jack falls unconscious. Sean and Chimalis leave him to die and strike out on their own. They encounter Red Knife, a celebrated warrior from Chimalis's River Crow tribe.
He leads them to a Crow village, where Chief Standing Lance and the council of elders agree to accept Sean as one of their own, and he becomes the adopted son of Red Knife and Chimalis. Sean learns the ways of the Crow, and his exploits in the ensuing years are the stuff of legends. He earns the name of Night Wind.
Threats to the Crows' way of life are many. The warring Lakota have feuded with the Crow for generations, and many on both sides are content to continue trading an eye for an eye. But Night Wind, having seen the unflinching viciousness of white settlers, believes that the tribes need to set aside old conflicts so that they might band together and defend themselves. With the help of Jim Beckwourth, war chief of the Mountain Crow and a former slave to whom Night Wind showed kindness back when he was just a boy, Night Wind attempts to lower tensions between the tribes and white settlers. But when his best friend Kicking Horse is killed needlessly by an overaggressive white man with a rifle, there is nothing he can do to prevent a hotheaded young raiding party from taking their revenge on nearby white settlers.
Night Wind races ahead of the raiding party to warn the unsuspecting settlers and finds that they are dying of a terrible pox. One of the boys in the family mistakes Night Wind for an attacking Indian and shoots him. Night Wind falls from his horse, shattering the Spirit Bow he has carried most of his life. If not for the Louis and Clark Peace Medallion that Night Wind has carried around his neck since he was a boy under Hatchet Jack's oppressive care, the bullet would have killed him. He loses consciousness before he can warn the family that their lives are in danger. Night Wind regains consciousness too late to warn his Crow brethren about the pox. They have killed the settlers, gained their revenge for Kicking Horse, and saved Night Wind's life, but at what cost? The after effects of his intervention change his life forever.