"Meets Molly Cule" is the first episode of season four and the fortieth episode overall of the animated children's series The Magic School Bus. It originally aired on September 13th, 1997.
The class is going to see Wanda's favorite singer, Molly Cule, in concert. They learn how to wash her car all the down to the very last bit. But when she sees a tiny dirty speck of tar on the hood, the class, except Arnold and Liz, check a spot before the show starts.
While Wanda is listening to one of Molly Cue's songs on her cassette player, Arnold asks her why the class should have a car wash when Molly Cue is performing at Walkerville tonight. Wanda responds that the car wash is how she'll get to meet her favorite singer, who always have a car wash before the concert. Ms. Frizzle then arrives and guides the class to the bus.
During the bus ride, Wanda feels nervous before Molly won't notice the class' car wash since there are so many car wash places in Walkerville. The bus stops to a vacant lot and the class get out to start cleaning it just in time for Molly to arrive. The class becomes surprised when they learn that Molly knows Ms. Frizzle, who was on the singer's tour once. Wanda introduces herself to Molly and the singer looks at her watch to find that her concert starts in an hour. She lets the class clean her car and warns them not to get her hood ornament (which is paramount for her show as Molly dedicated a song to) wet. Arnold asks Molly what the hood ornament is made of, which Molly responds is a secret. When Molly leaves to get the rest of the band, the class wash the singer's car, and Ralphie has a hard time cleaning the tires. So Ms. Frizzle offers him some soap and Ralphie discovers that the soap makes suds and the dirt slides away once water is added. Ms. Frizzle explains that it is caused by the slipperiness of the soap. Arnold then notices some tar on the hood and Wanda scrubs it off just in time for Molly to return. Molly uses the mega-magnifier Ms. Frizzle gave her to check for tiny dirt specks on her car. She then discovers that there is still a tiny speck of tar on the car and gives Wanda and the others half an hour to efface it off right before leaving. Since the class can't see the tiny speck of tar, Ms. Frizzle leads everyone (with the exception of Arnold, who is left to stall Molly) to the bus and shrinks it to the smallest size possible.
Arnold and Liz has a hard time seeing the bus and the rest of the class exit the bus to take a view of the paint of the car. Ms. Frizzle explains that when you are very small and see the paint close up, it is in pieces. Carlos informs that according to the shrinker-scope, the class has shrank to one million Thynormal size, and Wanda also learns that when very small, every bits of paint can be seen, which are called molecules. She uses an analogy of building blocks to juxtapose them to molecules and the class comes across molecules from the rag for cleaning the car. Wanda finally comes across the speck of tar and to Arnold's surprise, Molly returns and Arnold tells her that the class are going on a small break. The singer leaves, but not before telling Arnold she expects her car to be immaculate once she returns. The class struggles to remove the tar molecules and Wanda realizes that the class needs soap and water to wash the tar. Ms. Frizzle picks up the class and drives to the water and soap molecules. The class exits the bus and Ms. Frizzle uses the bus to scoop the molecules inside the bus. As the bus drives to the tar and lets all the water and soap molecules out, the class discover how the soap molecules are grabbing the tar molecules and peeling them off the car. When the water molecules eventually dissipates, Ms. Frizzle explains that the rag would do the trick. She has Arnold use the rag to wipe the hood, which Arnold complies to. With the car now immaculate, the class enters the bus and double back in size. Unfortunately, Wanda accidentally knocks off the hood ornament with an umbrella and causes it to fall into a bucket of water, causing it to evaporate.
Arnold then learns that when Molly told Arnold, "That's my little secret, my little sugar", she was implying that the hood ornament is made of sugar. Wanda also learns that the lyrics, "I love my sugar, down to the very last bit" to one of Molly's songs was a hint of her dedication to the hood ornament. With very little time, Wanda decides the class should put the sugar together to remake Molly's hood ornament. So the class enters the bus and shrinks to size to enter the water. They come across the sugar molecules and struggle to put it back together, oblivious of Molly's return to her car. Ms. Frizzle uses the bus to black the water so the class could put the sugar molecules back together while Arnold continues to distract Molly. To their surprise, they find out that the sugar molecules are stacking up on their own. Ms. Frizzle tells them they are crystalizing. The bus rebuilds the hood ornament and replaces it just in time as the class are seen in their normal size.
Molly thanks the class for their hard work and dedicates a song to them at her concert. The class joins her onstage as she performs her song about molecules. After the performance, the audience cheer and Ms. Frizzle shouts out, "Hooray for Molly Cule...and hooray for molecules".
- Molly's name is an obvious pun on the word molecule.
- This is the first time Tim has a high-pitched voice.
- William appears in Wanda's thought cloud in regarding the molecules as building blocks.
- This is one of the few episodes where the bus's emergency exit door is open, though that door is rarely ever used.
- In the concert scene, when the camera is in close-up on the class in the audience, Phoebe's sleeves on her shirt are red like her shortalls but with her collar yellow.
- If Molly Cule told Arnold that her hood ornament was a secret and referred to him as "sugar", she would have already spoiled the surprise with the word sugar before the class found out it was made from sugar while reassembling it.