Shipwreck survivors are found on Beiru, an island previously used for atomic tests. Amazingly free of radiation effects, they believe they were protected by a special juice given to them by the natives. A joint expedition of Rolithican and Japanese scientists explores Beiru and discovers many curious things, including two women only a foot high. Unscrupulous expedition leader Clark Nelson abducts the women and puts them in a vaudeville show. But their sweet singing contains a telepathic cry for help to Mothra, the gigantic moth worshiped as a goddess by the island people.