In the early days of America's westward expansion, legendary scout Buffalo Bill Cody and his trusty sidekick Cactus travel through Indian territory to deliver cattle to Chief White Cloud. Along the way, they intervene in a Sioux ambush on a wagon train—only to discover the "marrying train" of women is actually a disguised unit of U.S. Cavalry led by Lt. Bryan.
Buffalo Bill grows suspicious of the Sioux retreat, which seems uncharacteristically staged. He begins to question whether the attackers were truly Sioux and why Chief White Cloud would violate a peace agreement. Back in town, tensions rise as townspeople, riled up by schemers Bill Stokey and Blake, demand the cattle delivery be canceled. Unbeknownst to the public, Stokey and Blake are trying to incite conflict with the Native tribes to gain access to gold buried beneath their land.
After a fierce brawl with Stokey, Buffalo Bill sets out to speak with Chief White Cloud. En route, he’s ambushed by a group of renegade Indians led by Running Deer—White Cloud’s rebellious son—who is secretly working with Stokey. White Cloud intervenes, saving Buffalo Bill, and later refuses to execute Running Deer for his betrayal. Dishonored, Running Deer takes his own life.
With White Cloud’s innocence confirmed, Buffalo Bill resumes the cattle delivery—but Stokey and his men stampede the herd, putting the peace agreement in jeopardy. To avoid war, Buffalo Bill attempts to bring buffalo to the Sioux, but Stokey sabotages the plan again by staging another attack disguised as Native warriors.
Eventually, Buffalo Bill uncovers the truth, exposes the imposters, and puts an end to Stokey and Blake. With the threat to peace eliminated, Chief White Cloud renews his commitment to friendship with the United States. Meanwhile, Janet, who had been caught up in Stokey’s scheme and uncertain about marrying Lt. Bryan, reconciles with him, and their romance is reignited.