During the polio scare of the 1950s, a boy's parents send him for the summer from his small-towm Florida home to the refuge of his grandparents' farm in rural Alabama. He settles into country life with Papa and Bigmother. The locals nickname him Cracker, after the term for Florida cowboys. One day he and Papa go to a livestock auction and Papa lets him buy a small mule. The mule turns out to be blind and Cracker must suffer ridicule while caring for the animal he comes to love. Over the summer Cracker teaches the mule to respond to his voice and together they learn to plow. The summer passes with lazy days of fishing in the local creek mixed with frightening episodes involving poisonous snakes. In this idyllic setting, Cracker makes the transition from boy to young man.