Slaatn, an extraterrestrial voyager from the distant Arcturus star system, finds himself stranded on Earth's moon after an energy beam from the planet below has knocked his vessel off course and forced an emergency landing. To escape his lunar prison and resume his journey home, Slaatn must locate and neutralize a series of mysterious cubic transmitters scattered across the moon's surface, which are generating the powerful force field that has trapped him. The alien explorer's survival depends on systematically dismantling these installations and breaking free from the energy barrier that holds him captive.