Nobody understands Sly Fly, least of all other horse flies. In fact, they call Sly a fly misfit because he doesn't bite horses as they do. Sly Fly just doesn't fit in. Not to be discouraged, Sly and his unlikely horse friend, Gray Mare, hatch an ingenious scheme to keep other flies off of Gray. The story is humorous, and children will get a kick out of Sly Fly's outrageous antics and attire.