A new mule recruit arrives at Cheyenne Army Depot in the late 1800s. Commonly known as Camp Carlin, this supply depot had thirteen frontier army forts depending on deliveries to survive. Pack mules were an important part of that delivery system and had to be of good temperament and well-trained.

One young mule, Wild Bill, was proving to be difficult. Seemingly untameable, Wild Bill bucks, brays, and kicks his way through training. He and his young packer had a lot to prove in a limited amount of time. Will his trainer be able to calm him down or will he lose his position on the mule train?