A wagon train travelling from Independence, Missouri to Santa Fe means trouble for Alfredo Dupray, his authority from Spain will end with the arrival of a Mexican Governor.

He plots to solve this by intercepting a trade agreement, to be negotiated by Clark Stuart on the wagon train, and disrupt Mexico–United States relations.

Repeated attacks are thwarted, however, by the appearance of a mysterious Rider on a Painted Stallion who issues warnings with her whistling arrows.

With her help Clark Stuart, along with historical characters, Kit Carson, Jim Bowie and Davy Crockett work to defeat Dupray.

[3] Raymond Stedman describes Thyer as quiet yet impressive and William Nobles is noted for his sweeping camera work.