Utah Wagon Train (1951)

Rancher Rex Allen (Rex Allen) receives a summons from his uncle (Forrest Taylor), an old time frontiersman, that he is in trouble. The uncle has been hired to lead a modern-day band of adventurers on a wagon train retracing the route taken by their ancestors 100 years ago. Before Rex can talk to his uncle, the uncle is murdered, and Rex sets out to find the killer and the motive by taking his uncle's place as the leader of the wagon train. He discovers that the motive was the gold that the original pioneers had cached in a cave on the trail to California, and now has to find the culprit that is after it.