The mustangs are one of the oldest communities in Equestria, but hardly anything is known about them. All records and information are vague at best, but what is available is concerning. They live outside, use primitive stone tools, and eat grass from the ground like livestock.

Scientific curiosity piqued, Twilight ventures to the plains of Mustangia to see the mustang ponies for herself and introduce the modern world to a community trapped in the past.

But history points to a dark secret hidden just underneath the idyllic surface of the rolling hills. If Twilight digs too deep she may find something that was better off buried....