Burton introduces the episode by talking about cavern and cave exploring. The featured book, "The Magic School Bus Inside The Earth", is narrated by Keshia Knight Pulliam. Eccentric Ms. Frizzle takes her students on a science field trip to the center of the earth while teaching them about geology. Burton then visits California Caverns, where he learns about stalagmites, stalactites, and other crystal formations and goes spelunking with a cave expert.
