Massive UFOs, known as "mother ships," suddenly appear worldwide, originating from the Sirius star system. The aliens, who appear human, claim to come in peace, seeking Earth's chemicals to solve their planet's environmental issues. However, their true intentions are sinister: they are reptilian beings who view humans as a food source and are secretly draining Earth's water. Journalist Mike Donovan and Dr. Julie Parrish lead a resistance movement against these invaders, aided by rebel alien soldiers known as "the Fifth Column."
