Whiz eats the fruit of the deadly Laughing Bush and contracts a contagious and fatal laughing disease. Now the whole gang has to go on a mission to Dismal Swamp to find the Ding-A-Ling tree, the only known cure. They meet Cienega, the swamp monster, who offers her help. Can the Kidds get past her ugliness, or will judgment cause them to laugh to death?
