In a Pickle: Topic: Microbes; Keesha and the class return from vacation to find her prize cucumber has turned into a pickle! Could the Mike Robe gang be to blame? ; Meets Molly Cule: Topic: Molecules; When Wanda s favorite singer, Molly Cule, comes to town and she chooses Ms. Frizzle's class to wash her famous car, the kids discover how to clean the car down to the very last bit. ; Makes a Stink: Topic: Smell; Flora Whiff, the famous expert on smell -- whose nose knows -- comes to school to judge the First Annual Smell Search. Ms. Frizzle s class creates a unique smell that is bound to take first prize.