Charlie the plow mule lives on Cobble Stone Farm. Every morning, Charlie is used to getting up early and helping Farmer Brown plow the fields. One morning, though, something strange happens. Farmer Brown goes to plow the fields without Charlie.

Charlie is surprised to see Farmer Brown driving a new, shiny red tractor. Poor Charlie feels replaced. If the farmer doesn't need him anymore, will Charlie be sent away? Will he lose his home and all of his friends?

When Farmer Brown finds himself in trouble, Charlie, the farms strong plow mule, is called once again to help.