Saddlemates (1941)

When a strip of land along the Red River is declared in Indian Territory instead of Texas, the Rangers leave and the Army moves in. Now ex-rangers the Mesquiteers stay on as scouts. The new Colonel plans to make peace with the Indians but unknown to him the notorious Indian Wanechee is posing as his interpreter. The Mesquiteers learn of the masquerade but are not believed and instead are arrested just as Wanechee moves to wipe out the arriving wagon train.