An introverted TV songwriter, Mark Deveraux (Randy Quaid), inadvertantly brings millions of wise-cracking, joke-loving little green Martians to earth when he writes a theme score for a sweet love story.

But the music is accidently broadcast to the galaxies by his radio technical girlfriend. When the Martians begin to arrive the chaos begins! Mars' greenest inhabitants have interpreted the music as an open invitation to 'come on down' - and millions of them do!