Dr. Russell Marvin works for Operation Skyhook, a government task force sending rockets into space to probe for future space flights. But when the rockets begin mysteriously disappearing, Dr. Marvin investigates, only to find the rockets are being intercepted by an army of space aliens who give humanity an ultimatum: Loyalty or death! As the aliens begin attacking cities and landmarks across the Earth, its up to Dr.Marvin to figure out how to stop these creatures before its too late.