When the evil alien Zanon comes to enslave Earth, all hope seems lost. The Earth’s resident superheroes, the Spacewomen, are powerless to stop him. They must enlist the help of a young boy who has a special connection with the giant turtle Gamera. The Friend of All Children then battles Gyaos (a huge vampire bat/pterosaur hybrid), Zigra (an alien shark), Viras (an alien squid), Jiger (a female giant prehistoric dinosaur), Guiron (a knife-headed alien monster) and finally Barugon (an enormous lizard whose tongue sprays a freeze-gas that can freeze things solid and whose back spines emit a powerful rainbow ray that can melt or dissolve any solid object). Gamera sacrifices his life in the end to destroy Zanon once and for all and to protect Earth one last time.