In the year 2030, Earth is invaded by aliens, causing widespread destruction and killing most of the human population. The few remaining humans are saved by a group of powerful alien warriors called Kaktat, who take them to a new planet where they can live safely. One hundred years later, humans discover that they can gain superhuman powers by using gems found inside alien creatures Rex, a 17-year-old orphan, dreams of becoming a warrior and hunting aliens. He sets out to attend a military school, leaving behind his old life and looking forward to a new beginning.