The relationship between man and his noble steed is almost as old as civilization itself, allowing our species to explore, conquer and flourish side by side with the horse. Nature traces this revolutionizing partnership with anthropologist Niobe Thompson, who treks around the world in search of the moment when man first climbed into the saddle and explains how the relationship between humans and horses has evolved in today’s modern world. Discover the habits of these majestic animals and their unique biological makeup, which made them a perfect fit for our ancestors. Ride along with the world’s last nomadic tribes, who view the horse not just as an animal, but a means of survival. Witness the return of horses to the wild as mankind preserves the hardest-working animal partners we’ve ever had. Locations in this two-part series include Mongolia, Montana, Kentucky, Saudi Arabia, Canada, Siberia, and Sable Island, Nova Scotia.