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.