一位普通白领青年（田口智朗饰）在地铁站被手上有着铁爪的神秘女人（叶冈伸饰）袭击追杀。一番打斗后返家，他在色情幻想中发现自己的身体竟正在钢铁化，下身变为巨大的钻头，拥有了极其可怕的力量，他的女友（藤原京饰）成为了变身的祭品，而他最终变为一个金属的怪物。
　　这时来历不明的男子（冢本晋也饰）出现，原来他在青年造成的车祸中大难不死，并因此获得超能力，他的憎恨力量导致了以上所有事情的出现,产生,形成,酿成。一个由钢铁打造的躯体，一个神秘的超能力者，他们将展开可怕的对决。

　　Shipwreck survivors are found on Beiru Island (Infanto tô), which was previously used for atomic tests. The interior is amazingly free of radiation effects, and they believe that they were protected by a special juice that was given to them by the island's residents. A joint expedition of Rolisican and Japanese scientists explores Beiru and discovers many curious things, including two women only one foot (30 centimeters) 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, a gigantic moth that is worshiped as a deity by the island people. The giant monster heeds the call of the women and heads to Tokyo, wreaking destruction in its path.