The Earthlings are sneaking into a circus to steal explosives when an escaped gorilla captures Valerie. With the aid of an elderly puppeteer, Goalby, Valerie is rescued. Betty then wanders into a bear trap, and Goalby frees her but injures his right hand.
Betty and Fitzhugh decided to help Goalby win his audition by becoming "puppets." The circus owner, Brady, captures Valerie and Dan and realizes Goalby's puppets must also be little people. He captures Fitzhugh and Betty, and forces them to work for him by threatening the other two.
Mark and Steve stage a rescue by using some of the explosives to blow open the gorilla's cage. It attacks Brady, while Goalby and his assistant Lisa free the four captive Earthlings. In return, Steve, Mark, and Fitzhugh provide Goalby with some new techniques and a recording of their musical number so that he can become a hit.