Smedley S. Snerd, a typical nerd hero, is the star student of Miss Fossil's geology class. He's got a big crush on Marybelle Moosenheimer, the heroine, star cheerleader, and member of the Locks, a group which values their beautiful hair. Other peer groups include the Rocks, who are into "heavy metal"; the Jocks, who are athletically inclined; and the Rolls, a gang of hoodlums led by the infamous macho villain, Mr. G. But brain outwits brawn as Smedley uses his marbles to trip up Mr. G and his gang, win Marybelle's hand, and explain to Miss Fossil the real origins of rock and roll.