Descended from a long line of ramblers and rogues, Jack Picaro came to America to seek his fortune. But after killing his best friend in a drunken duel, the apprentice gunsmith flees westward, leaving behind children he does not know, Gus and April. As Jack ventures up the Missouri River, he finds an unspoiled land where a man can live free, and also be attacked by an Arikara war party. His rifle stolen in the bloody skirmish, Jack sets out alone to reclaim it. His wild escapade ends in a fight to the death with a legendary Crow warrior named Standing Wolf.