Unusual volcanic activity in Japan awakens Gyaos, a bloodthirsty flying monster with the power to slice things in half with an ultrasonic ray. While scientists and the military scramble to devise a way to stop this new threat, a young boy forms an alliance with Gamera; a monster no one else seems to trust.
A moon base is destroyed by a spaceship from Zigra which is looking to take over the planet earth to use its oceans for its ocean-dwelling denizens. Gamera must once again come to the aid of the human race while all of Japan roots him on.
As a massive alien craft heads to Earth to do evil, three good and powerful superwomen befriend a young boy who has a special connection to Gamera. The alien Zanon launches a battery of familiar foes against Gamera, who might have to give the ultimate sacrifice to defeat the alien invader.
