Autry Braden and Ed Talley aim to join George Mason and hunt mustangs in 1804 Spanish Texas. Their mission intersects with Maria Manuel, who is running from Juan Castenada, captain of the Spanish garrison at Nacogdoches. Maria takes refuge with the mustanging trio as they move into mustang country, where they encounter the legendary golden stallion and his brood of mares. They work to acquaint the mustangs with their presence, build a pen to trap them in, and trail break them once they are captured. In the interim, Castenada has decided to claim the mustangs for his own. On the return trip, all the interweaving animosities boil over in a variety of showdowns.