Mighty Joe Young is a 15-foot African gorilla. His best friend and protector is Jill Young. Against her better judgment, Jill allows Joe to be brought to the States as a nightclub attraction. He later breaks loose and goes on a rampage.
A gorilla lets other zoo creatures out of their cages; a bear wants to get the moon a birthday present; an old woman takes a nap with all the critters in her house; an old couple wants children and the moon helps them.