Sebastian, a twenty-first century boy, finds himself living amongst the Blackfoot people, but in a time before any European had set foot in America.
Vast herds of buffalo roam the plains, and the Blackfoot tribe's survival depends on the annual buffalo jump, when a herd of buffalo are driven over a cliff for their meat and hides. Head-Smashed-In Buffalo Jump is such a cliff, and it is said that its name derives from the legend of a Blackfoot boy who foolishly watched from the base of the cliff as the buffalo fell.
As the tribe prepares for the day of the buffalo jump, Sebastian's bond with his Blackfoot brother, Four Falcons, grows ever stronger. Through his adventures with Four Falcons, Sebastian's life becomes entwined in the legend of Head-Smashed-In Buffalo Jump, until the legend and the boy become one.