The life and times of an Arkansas roadhouse band called The Highway 70 Six, circa the 1950s. The ""Watermelon Kid"" of the title is sweet-natured A. J. Poole, who earned his name thanks to a winning effort in a bygone watermelon-eating contest--a triumph which he handled with great modesty and grace. But the other members of the Six brawl as regularly as they sing. (The two most memorable band-members: lead singer Doodle Socket, who's forever waiting for Ed Sullivan to get around to calling with a TV offer; and ""nightclub stander"" Rainbow Wimberly--who simply gets up on a table and very slowly revolves. . . statuesquely.) So A.J.'s quick wits and devious puttings-to-right come in quite handy through their various misadventures. . . leading up to a beauty contest, with Rainbow the prime contestant. Nothing very substantial, more material for smiles than laughs--but silly, headlong fun, speeding smoothly along with some of the natural good-ol'-boy comedy that distinguished Charles Portis' Dog of the South.