Johnny loves his uncle and his master's mule, but he hates being a slave. So when he's asked to join the Union army, he accepts. Being a soldier is hard work, and Johnny wonders if he made the right choice. But when the army needs him, Johnny knows it's up to him to come to the rescue!

A boy who hates being a slave joins the Union Army to fight for freedom, and proves himself brave and capable of handling a mule team when the need arises.