"Terra" is Latin for Earth.
After a spaceship transports the two Japanese kids, Akio and Tom, to the planet, they meet two of the planet's native aliens. The Aliens explain that Terra is on the opposite side of the Solar System to Earth, and that they are the last of their kind. They also reveal that the planet is being plagued by swarms of Space Gyaos, and send out Guiron to fight one. After Guiron kills the Gyaos, the true intentions of the Aliens are revealed - they desire to eat the kids' brains! Shortly afterwards, Gamera arrives to fight Guiron, and loses the first battle. Guiron then goes berserk and attacks the Terrans' base, killing both the cannibalistic aliens. Gamera is successfully revived, and battles Guiron again, killing him, then taking the two kids home. It is assumed that after this, Terra became a home for the swarms of Space Gyaos.
- 'Terra' is Latin for Earth. This explains why Terra sits on the opposite side of the Solar System, because it can be considered to be a parallel planet to Earth.
- Although very little grows on the planet's surface, Terra's waters appear to host a variety of different plants and corals, as shown when Gamera falls into the water and becomes unconscious.