the sun directly opposite the earth, which is why it has never been discovered by Earth's astronomers. Furthermore, Terra is facing extinction; not only is the planet growing cold, but the Space Gyaos are taking it over and the two women are the last of their kind. The knife-headed monster, which the Terrans call "Guiron", is their last defense against the Space Gyaos. Barbella and Florbella suddenly incapacitate Tom and Akio and put them into restraints. Using their super-technological devices, the alien women probe the boys' minds, in the process learning about Gamera and his soft spot for children. It is revealed that the Terran women are cannibals that plan to feed on the boys' brains in order to absorb their knowledge. In preparation to extract Akio's brain for their nourishment, the women shave the child's head. On a rescue mission, Gamera lands on Terra in search of the boys. The women deploy Guiron to attack the giant turtle. Guiron plans to cut Gamera in half, but Gamera grabs one of Guiron's front legs and bites into it. Guiron tries to shake off the towering tortoise. Wrapping his tail onto a monolith, Gamera throws Guiron into a canyon, causing his knife-head to be stuck. Gamera uses his flame breath on Guiron. Guiron uses his shurikens to penetrate Gamera's cheeks. Gamera tries to heal his wounds by grabbing ice-like boulders. Guiron uses his shurikens again and this time Gamera uses a long boulder to ricochet the shurikens into Guiron's own body. Guiron trudges away, while Gamera tumbles into a lake unconscious and on his back. Tom wakes up and manages to free Akio, but, during their escape attempt, unintentionally releases Guiron. No longer under the aliens' control, Guiron rampages through the Terran city — even attacking his own mistresses as they attempt to flee to Earth. The knife-headed creature slices the spacecraft in half, mortally injuring Barbella; Florbella kills Barbella as she relates that useless members of their society are euthanized. While Guiron attacks the base where the boys are imprisoned, Gamera awakes and renews his assault on the alien creature, ultimately ramming Guiron's head into the ground. Florbella attempts to flee on a rocket, but the boys launch missiles that destroy her rocket and she dies as a result. Gamera catches one of the missiles and spears Guiron into his shuriken base. Gamera uses his flame breath on Guiron again