In the year 2199, an alien race known as Gamilas (Gamilons in the English "Star Blazers" dub) unleash radioactive meteorite bombs on Earth, rendering the planet's surface uninhabitable. Humanity has retreated into deep underground cities, but the radioactivity is slowly affecting them as well, with humanity's extinction estimated in one year. Earth has a space fleet, but they do not yet have interstellar capability, and they are hopelessly outclassed by Gamilas. All seems lost until a message capsule from a mysterious crashed spaceship is retrieved on Mars. The capsule yields blueprints for a faster-than-light engine and an offering of help from Queen Starsha of the planet Iscandar in the Large Magellanic Cloud. She says that her planet has a device, the Cosmo-Cleaner D (Cosmo DNA), which can cleanse Earth of its radiation damage.