President James Dale (Nicholson) of the United States and his right-hand man, Jerry Ross (Short) discover that an army of Martian UFOs are hovering around the Earth, and everyone has a different response. Some, like Texan alcohol dealer Art Land (Nicholson) and slimy newsman Jason Stone (Fox), just want to make a profit out of it. Others, such as TV hostess Nathalie Lake (Parker), Land's spiritualist wife Barbara (Bening), and the Southern-like Norris family, are excited, and some, like Dale's wife, Marsha (Close), and daughter, Taffy (Portman), don't care. Richie Norris (Haas)is extremely unintelligent but is only respected by his insane grandmother, while his older brother Billy (Black) is favored for joining the army. General Decker (Steiger) doesn't trust the Martians and insist they fight, but General Casey (Winfield) & Professor Kessler (Brosnan) are more optimistic. The Martians appear to come in peace but suddenly begin to use their super-powerful and technologically advanced weapons to wipe out the population and great structures. Will anybody find a way to stop them or will they all die in the war with these short, big-brained aliens?