A fur trapper named Kelly, who once saved the life of a Sioux chief is allowed to set his traps in Sioux territory. He takes on a tenderfoot assistant named Anse and together they give shelter to Wahleeah, who has run away from her Sioux captors. The Chief allows the woman to stay for a while with Kelly and Anse, over the objections of Sayapi, the Chief's nephew. In the meantime, a garrison of Calvary is planning to cross the Yellowstone River to drive the Sioux north. Sayapi returns to Kelly's cabin while Kelly is away, kills Anse, and takes Waheelah. Kelly tracks the kidnappers down and takes Waheelah, who wants to go north to her own tribe, the Crow. As the two go north they run into what remains of the garrison, which has suffered many casualties at the hands of the Sioux. Kelly and the girl stay with the soldiers as they meet the Indians in a battle to the death.