Mustang genes are like those of our country: mixed and mingled, influenced by wave after wave of immigration. Mainstream science tells us the modern-day mustang is descended from horses brought over by the Conquistadors, who used them to subjugate the Indigenous peoples of Central America. But what if the horse wasn’t introduced by newcomers, but was here all along, living alongside the Indigenous peoples of North America? Meanwhile, back at the ranch, while Boo eats his breakfast one morning, Ashley plucks some of his mane to send off to a genetics lab to find out what Boo’s genes can tell us about the history of wild horses.