The Road to Fort Alamo (1964)

A solitary horseman discovers a mortally wounded soldier, the lone survivor of an Indian ambush, who presses into his hands a document promising $150,000 to the U.S. Army. The rider recruits a band of confederates, they masquerade as soldiers, and present the paper at a bank. The money is handed over, but gunfire erupts, an elderly woman is slain, and the gang parts in bitter discord. Eventually, several members cross paths with genuine U.S. Cavalry troops, and together they must repel fresh waves of Indian assaults.