A group of scientists on Sollgel Island are conducting weather control experiments. They keep encountering strange interference with their equipment, as well as human-sized mantids lurking in the jungle. A reporter named Goro Maki (Akira Kubo) parachutes onto the island, and with no way to send him home, they have no choice but to let him stay for the experiment.
The experiment goes terribly wrong, causing intense heat and radioactive rain to fall onto the island. When the radioactive storm is over, the strange mantids have grown to giant monster size. The mantids, called Kamacuras, dig a giant egg out of the ground, which turns out to be the source of the interference that had been messing with the scientists’ equipment. The Kamacuras break open the egg, revealing Minya, a baby Godzilla. Godzilla comes ashore and fights off the Kamacuras, killing two of the three of them before they can eat Minya.
The scientists also find a woman living on the island named Saeko Matsumiya (Beverly Maeda). She and Goro begin to fall in love as the scientists prepare to do the weather control experiment again and Godzilla teaches Minya to breath atomic fire.
Soon a giant spider named Kumonga, which was sleeping underground on the island, wakes up. It manages to catch and kill the last Kamacuras, and then ensnares Minya in its web. Just as Kumonga is about to kill Minya with an injection of venom, Godzilla comes to the rescue. While Godzilla and Minya battle Kumonga, the scientists try their weather control experiment again. The experiment is a success, blanketing the tropical Sollgel Island in snow. Godzilla and Minya defeat Kumonga and go into hibernation as the scientists leave Sollgel Island.
Son of Godzilla was one of two giant monster movies produced by Toho in 1967. The other one, King Kong Escapes, was a co-production with American company Rankin/Bass. Three more of Japan’s top film production companies also put out a giant monster movie in 1967: Shochiku released The X from Outer Space, Nikkatsu released Giant Monster Gappa, and Daiei released Gamera vs. Gyaos.
As King Kong Escapes was a co-production with American company Rankin/Bass, it had the bigger budget of Toho’s two monster movies of that year. Like the budget-conscious Ebirah, Horror of the Deep, Son of Godzilla is an island-set film without any scenes of urban destruction. Still, the special effects work in this film is plentiful and, for the most part, really well done. The Kamacuras and Kumonga are not portrayed by suitmation, but rather are giant marionettes which, in some scenes, required over 20 operators. Godzilla fights his enemies in the jungle and in clearings this time, instead of in the water, and the miniature island sets all look great.
The human characters are very likeable and the cast is made up of a number of Godzilla film veterans: Tadao Takashima plays Professor Kusumi, Akira Kubo plays reporter Goro Maki, while Kenji Sahara and Akihiko Hirata play scientist team-members Morio and Fujisaki. One of the more interesting characters is Furukawa, played by Yoshio Tsuchiya, who slowly has a mental breakdown from his confinement on the island. Beverly Maeda makes her sole appearance in a Godzilla film as the island girl who bonds with Goro Maki and Minya.
Son of Godzilla is a very light-hearted film and features some of the most anthropomorphic behaviour from a monster in a Godzilla movie thus far. Minya was designed to be cute and entertains himself by jumping over a sleeping Godzilla’s swinging tail. He also interacts with the human cast on occasion, such as catching fruit thrown into his mouth by Saeko. There is also a scene where Godzilla teaches him to breath atomic fire, the baby monster only capable of blowing smoke rings at first.
One theme central to the film is parent-child relationships. Godzilla takes care of his son, letting Minya skip over his tail, and comes to the rescue when the little monster is attacked by Kamacuras and Kumonga. In the end, they work together to bring the giant spider down, with Minya using his atomic breath to save Godzilla, just as he had been taught by dad.
This film also has an environmental theme to it. The scientists are attempting to manipulate the weather, turning the tropical island into a snow-covered one. The scientists show no regard for the island’s unusual human-sized praying mantids, ignoring this new species to press forward in their attempt to play God. This experiment goes wrong, resulting in high temperatures, a radioactive rain storm, and mutated giant mantids. The obvious long-term goal of such experiments is to allow for better food growing conditions for us humans, something that would require the mass destruction of natural ecosystems, the first of which is Sollgel Island itself.
Son of Godzilla was released direct to television in North America by Walter Reade Organization in 1969. The movie was dubbed into English by Titan Productions in the United States and only a few minor edits were made to the very beginning of the film.
In 2004, TriStar released Toho’s international version of Son of Godzilla on DVD. This version had the onscreen titles changed to English, and viewers could choose to watch it with the original Japanese audio or Toho’s own English dub, which was produced at Frontier Enterprises in Japan. This DVD is now out of print. The original Japanese version of Son of Godzilla, with Toho’s own English dub as an alternate audio option, is currently available as part of The Criterion Collection’s Godzilla: The Showa-Era Films, 1954-1975 Blu-ray set.