A lowly janitor aboard the scientific vessel Arcada awakens from a nap in a broom closet to discover the ship under attack by an alien faction known as the Sariens, who have seized a powerful experimental device called the Star Generator. Escaping via pod, the protagonist crash-lands on the arid planet Kerona, where he must navigate hostile terrain and underground caverns to survive. After proving himself by defeating a fearsome local creature and earning favor with an insectoid inhabitant, he acquires transportation and eventually reaches the frontier town of Ulence Flats, where fortune at a slot machine provides him the means to purchase a ship. Learning the location of the Sarien vessel Deltaur, he infiltrates the enemy craft through a series of improvised and unconventional methods, from disguise to infiltration, ultimately reaching the Star Generator and triggering its self-destruct sequence before barely escaping the explosion.