Wanda's favorite music star, Molly Cule (voiced by Wynonna Judd), is coming to Walkerville. Wanda wants to have the great honor of washing her car. The class set up a car wash. Molly Cule miraculously chooses theirs over automatic car washes. The reason for this is explained when Molly Cule says that she cannot afford to have her hood ornament get wet. When Arnold asks what it's made of, she says, "That's my little secret, Sugar." She continues to call Arnold "Sugar" for the remainder of the episode. After they clean the car, she found a tiny blot of tar on the car using a "megamagnifier." The class shrinks down to the size of molecules to find it, and clean it off. However, when they get back Wanda accidentally knocks Molly's hood ornament into a bucket of water. It occurs to Arnold that her hood ornament is made from sugar, from what she said when he asked her what it was made from. The class shrinks down to the size of molecules to rebuilt the hood ornament. After they start, the sugar molecules begin to crystallize, the ornament gets put back together before Molly returns. The class then gets to participate in Molly's concert.