SOS Earth! Revive Space Battleship Yamato!.In the late 22nd century, an alien race known as the Gamilons have attacked the Earth, bombarding it with radioactive bombs and forcing the population underground. However, the radiation is seeping into the planet; unless it's removed, Earth will become uninhabitable in one year. War with the Gamilons has also destroyed the Earth's space forces except for two ships -- the Paladin, commanded by Alex Wildstar, and another ship, commanded by Captain Avatar. During a battle at Pluto, Avatar's ship is damaged. The Paladin gives Avatar's ship enough time to escape, but is destroyed in the process. Meanwhile, a non-Gamilon alien ship is hit in the crossfire and crashes on Mars. Cadets Derek Wildstar, Alex's younger brother, and Mark Venture investigate and discover a beautiful, dead woman, ejected from the escape pod and clutching a message capsule. They return to Earth in Avatar's battleship, and Derek notices the absence of any other ships. On the way back, they learn of Alex's fate. After they return, Derek confronts Avatar about Alex, but Avatar says it was Alex's decision to remain. When the message capsule is decoded, it contains a message from Queen Starsha of planet Iscandar. Starsha says the messenger was her sister, Astra, and offers Earth the Cosmo DNA, a device which can remove the radioactivity. The message also contains plans for an advanced-technology Wave Motion Engine -- capable of faster-than-light travel. As the Earth Defence Command deliberates, a Gamilon recon plane is detected sniffing around the ruins of the sunken WWII battleship, the Yamato. Out of sheer boredom, Wildstar and Venture take a plane out (unauthorised) to investigate. The Yamato appears to be nothing more than a hunk of ruins, however, leaving the cadets puzzled as to why Gamilon would be interested in it.