Teenager Sam Shepherd has always dreamed of one day becoming an astronaut like his late father, but a weak heart has kept him planet-bound. That all changes when two warring aliens crash in his hometown and seek him out for help. Sam must now try to protect the soldier of the Firestar Confederacy and the emissary for the Shovain Star Empire from the Galv - a parasitic race intent on destroying both of their species - and prevent them from conquering Earth and expanding their reach. With the fate of two galaxies and his own planet in his hands, Sam embarks on a heart-pounding adventure to save the universe.