Tractor Mac is hard at work in the field one day when his engine starts to make a funny noise. It doesn't sound good, and it doesn't feel very good, either. Tractor Mac is scared that he has to take a trip to Dr. Lou at the tractor hospital, but with the help of his animal friends and some other machines who have stopped in for a tune-up, he learns that going to the doctor doesn't have to be scary at all.