Ms. Frizzle has a very interesting lesson for her students, today! She intends to teach them all about diapers! And with a snap of her fingers, her class is going to learn about them first hand, as they look down and suddenly realize they have been diapered! Layla and Larry are not happy about being diapered, so they decide Ms. Frizzle needs to practice what she preaches. Layla snaps her fingers and suddenly Ms. Frizzle has been diapered too! The quirky teacher laughs and tells the students to change her back, but they refuse. So with another snap of her fingers, Layla and Larry lose control of their bladders and start to wet their diapers! The students are so embarrassed, but they're not going to let their teacher get away with this. Layla snaps her fingers again, and within seconds Ms. Frizzle is wetting her own diaper! Now all of them are stuck in this lesson with soaking wet diapers. Layla asks if Ms. Frizzle can just change them back, but she informs them that they've already run over budget for this episode, so they're just going to have to finish out the class in their wet diapers!