Its basic plot was recycled in King Kong vs. Godzilla and Mothra vs. Godzilla (1962 and 1964, both also written by Sekizawa), and Mothra would become Toho's second most popular kaiju character after Godzilla, appearing in seven Godzilla sequels and her own trilogy in the 1990s.
An expedition to an irradiated island brings civilization in contact with a primitive native culture. When one sensationalist entrepreneur tries to exploit the islanders, their ancient deity arises in retaliation.
In waters off Infant Island, a presumed uninhabited site for Rolisican atomic tests, the Daini-Gen'you-Maru is caught and run aground in the turbulence of a typhoon. A rescue party following the storm finds four sailors alive and strangely unafflicted with radiation sickness, which they attribute to the juice provided them by island natives. The story is broken by tenacious reporter Zenichiro (also known as "Bulldog" or "Zen-chan") Fukuda (Sakai) and photographer Michi Hanamura (Kagawa), who infiltrate the hospital examining the survivors.
The Rolisican Embassy responds by co-sponsoring a joint Japanese–Rolisican scientific expediction to Infant Island, led by capitalist Clark Nelson (Ito). Also on the expedition are radiation specialist Dr. Harada (Ken Uehara), linguist/anthropologist Shin'ichi Chūjō (Koizumi), and stowaway reporter Fukuda. Chūjō has studied the cultures of islands in the area and ascertained that one of the key hieroglyphs in their written language, a radiant cross-shaped star, translates as Mothra.
Nelson, however, returns to the island with a crew of henchmen and abducts the girls, gunning down several natives who try to save them. While Nelson profits off a "Secret Fairies Show" in Tokyo featuring the girls singing, both they and the island natives beseech their god Mothra, a giant egg, for help. Fukuda, Hanamura, and Chūjō communicate with the young women via telepathy; they express conviction that Mothra will come to their aid and warn that "good people are sure to be hurt". Meanwhile, Fukuda's newspaper has accused Nelson of holding the girls against their will; Nelson denies the charge and files a libel suit against the paper. Meanwhile, the island egg hatches to reveal a gigantic caterpillar, which begins swimming the Pacific Ocean toward Japan. The caterpillar destroys a cruise ship and survives a napalm attack on a beeline path for Tokyo. The Rolisican Embassy, however, defends Nelson's property rights over the girls, ignoring any connection to the monster.
- Frankie Sakai as Zen'ichiro 'Zen-Chan' Fukuda, Nitto Journalist
- Kyōko Kagawa as Michi Hanamura, Nitto Photographer
- Hiroshi Koizumi as Dr. Shin'ichi Chujo
- Ken Uehara as Dr. Harada
- Jerry Ito as Clark Nelson
- The Peanuts, Yumi Ito, Emi Ito as The Little Beauties
- Takashi Shimura as Sadakatsu Amano, Nitto Editor
- Masamitsu Tayama as Shinji Chujo
- Kenji Sahara as Helicopter Pilot
- Akihiko Hirata as Doctor
Based on the novel The Luminous Fairies and Mothra, this adaptation was penned by Shinichi Sekizawa, who submitted his first draft proposal in 1960. Vaguely titled The Giant Monster Thing, this early concept featured a race of tiny women alongside the movie's giant monster. A name for the fairies was not specified in this first proposal, as apparently even at this early stage Sekizawa was contemplating a name change from their original title of the "Airenas" from the book.
In an unusual turn of events, another draft proposal was submitted shortly after. Re-titled Giant Monster Mothra, this second proposal fleshed out the concept more, giving the small women the name of the "Pichi Fairies" while citing that five would be seen during the course of the film. The size of the Pichi Fairies was stated as being 60 centimeters, showing a strange level of detail in this respect for a draft proposal. For reference, that would have been roughly twice the size of the final "Shobijin." The idea was seen as a winner, as a more fleshed out screenplay was finally commissioned.
On January 14, 1961, the second draft of Giant Monster Mothra was submitted. Since the first draft, the singing duet The Peanuts (Emi and Yumi Ito) had been attached to the production. Seeing a very lucrative idea in the making, the fairy role was altered to just that of the singing duo, while their name was also changed to the Shobijin. The concept would be altered even further by Sekizawa, as a third draft of the script was submitted on February 5 of that same year. Production on the movie was now in full swing, although the name Giant Monster Mothra hanged around for quite a while, even being used on advance posters before it was shortened to simply Mothra (1961) for its final release.
The original climax for Mothra was entirely different from what ended up in the final print. Originally, Nelson and his group had planned to kidnap Shinji Chujo for a longer period of time, rather than leaving him tied up as they fled the country. Instead, they took the small boy on a private plane as they attempted to flee, only to accidentally crash near a mountainside. Meanwhile, the film's heroes are in close pursuit, having brought along the authorities to help save the boy. All of this takes place while Mothra is still in its cocoon, meaning that Fukuda and the others weren't originally planned to witness the birth of Mothra's adult form. Instead they give chase to Nelson as Mothra breaks free after the Atomic Heat Ray Gun attack. She then immediately flies to the mountainside, kills Nelson and goes back to Infant Island with the Shobijin.
Mothra was released in Japan on July 30, 1961 where it was distributed by Toho.
Mothra was released by Columbia Pictures with an English dub on May 10, 1962. This version had an 90 minute running time.
The film has been re-released theatrically in Japan since its release. This includes a shorter version of the film distributed by Toho with a 62 minute running time on December 14, 1974. This version was edited by Ishiro Honda. Mothra was re-released theatrically in Japan on November 21, 1982 as part of Toho's 50th anniversary.
Film critic A. H. Weiler in The New York Times gave the film a generally positive review, singling out the color and special effects for praise. "There's that color, as pretty as can be, that now and then smites the eye with some genuinely artistic panoramas and décor designs."
Columbia TriStar (Sony)
Released: August 18, 2009 (as part of Icons of Sci-Fi: Toho Collection, along with The H-Man and Battle in Outer Space)
Mill Creek Entertainment
Released: February 25, 2014 as part of Sci-Fi Creature Classics, along with 20 Million Miles To Earth, The Giant Claw and It Came From Beneath The Sea. (Note: Mothra is presented in anamorphic widescreen though the DVD case mislabels it as being in letterbox.)