Ben Bowie and His Mountain Men #7

Ben Bowie, Jim, Zeke, and Nakah travel west of the Mississippi and stop at Fort Lisa on the Missouri, where they encounter Sioux Indians playing lacrosse. A prophet among the tribes calls for an alliance of Kiowas, Pawnees, and Cheyennes to unite against white encroachment on their hunting grounds, proposing they bury their differences and make peace with all their red brothers to drive the white man away. The mountain men must navigate the tense situation as the prophet rallies the tribes to his cause.