Sandor and Homer travel to Earth with Major Cranshaw, one of Desslok's scientists. After meeting the Earth Defense Force's commander, Cranshaw takes one ship to Saturn while Sandor and Homer follow in a second ship. Sandor explains the plan: first, Cranshaw will launch specially designed missiles to form a magnetic shield around the sun. Then Sandor's group will launch special missiles to gather asteroid fragments and send them into the sun. Finally, Cranshaw will launch proton missiles, and the resulting reaction will return the sun to normal. At first, the plan appears to succeed, with the sun's temperature falling, but it then rapidly rises, forcing both ships to immediately retreat. Humiliated by the failure, Cranshaw orders his men to abandon his ship, then commits suicide by flying it into the sun. Derek and Nova offer their condolences to Desslok on the loss of Major Cranshaw. Desslok wishes Derek and Nova success on their mission. As Derek and Nova leave, they see several of Queen Guardiana's worshippers. Derek asks Desslok about the worshippers, and Desslok simply says Galman does not need two gods. He then tells the Star Force about another planet – Phantom – which is similar to Earth and supposedly uninhabited. 153 days remain before the sun destroys Earth.

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. This event becomes a major motivator for Derek Wildstar throughout the series. 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 propulsion technology, dubbed the Wave Motion Engine, capable of faster-than-light travel. As the Earth Defense Command deliberates, a Gamilon recon plane is detected sniffing around the ruins of the sunken World War II battleship, the Yamato. Out of sheer boredom, Wildstar and Venture take a plane out (unauthorized) to investigate. However, the Yamato appears to be nothing more than a hunk of ruins, leaving the cadets puzzled as to why Gamilon would be interested in it.