Genius twins Coke and Pepsi McDonald embark on a trip to Graceland and are horrified by the reappearance of their supposedly deceased arch nemesis Dr. Herman Warsaw, who marries their aunt Judy.
As their cross-country journey with their parents continues through the midwest, twins Coke and Pepsi, now thirteen, again face strange assassins at such places as the first McDonald's restaurant and Cedar Point amusement park.