Featuring the song: Are You Going to Find Out (Yes I am)

Original air date: 10/06/73
Written by Marc Richards - Directed by Hal Sutherland
Storyline: Professor Fahrenheit has been altering gravity and stealing mass quantities of valuable metals, so Miss Tickle and the kids go to the City inside the Earth to get to the bottom of things.

According to US

Miss Tickle takes the club to Carlsbad Caverns by shrinking them so they can fit Tut-Tut's milk saucer.  Rick calls Miss Tickle from The City Inside the Earth telling them to come right away.  Miss Tickle draws a magic door that they go though to get there. When they get there, they find that gravity is out of control.  Rick tells them that large quantities of Metal have been disappearing from the Surface of the Earth, and he has tracked them to where they are now. Miss Tickle asks Rick if he knows who is behind it and he says he doesn't have a clue.  Then the song "Are You Going To Find Out (Yes I Am) plays, which ties the song into the episode. They do find out that the culprit is Professor Fahrenheit. Miss Tickle's magic isn't working, so they all hold hands to help her magic. The Ptolemy helps them get out from where they are trapped. Miss Tickle restores everything back to normal. Professor Fahrenheit's sidekick Simon is probably the funniest part of this episode. - rlh