Quaid plays a song writer who accidentally invites a billion Martians (all portrayed by stand-up comedians from the late eighties and early nineties) to planet Earth.
In 1966 a U. S. military station in Houston, the United States Decoding Service (U.S.D.S.), NASA Wing, has intercepted a message. After decoding, the message contains only the cryptic statement: "Mars ... Needs ... Women".
Five friends engage in a night of heavy drinking, fighting, and carousing at a club. Hung-over, they drunkenly stumble out of Robin's house, where they crashed for the night, and discover that nobody on their street has mobile phone service or power. They are confronted by an apparently deranged tramp who insists that they are in danger from people with a purple mark. When a city-sized spaceship hovers over Derby, the city begins to panic and society begins to break down. Michael, a lieutenant in the SAS, attempts to lead his friends to safety. He is accompanied by his new girlfriend Carrie, whom he met the previous evening at a nightclub, his best friend Robin, Robin's fiance Dana, and Vincent. They make their way to a store where their friend Pete works, but it is closed. The group rescues an immigrant from angry thugs, and Pete allows the group in through the side entrance. However, a riot breaks out when the crowd sees them gathering supplies, and looters attempt to steal their groceries. Michael frightens off the looters with a pistol, and the friends head back to Robin's house.
John Carter (Antonio Sabato, Jr.) is a modern-day U.S. Army sniper serving in Afghanistan, wounded in the line of duty and used in a teleportation experiment wherein he is transferred to Barsoom, here depicted outside our solar system. On this world, Carter exhibits the ability to leap amazing distances. Initially enslaved and held against his will on a chain and collar by the Tharks, he earns a rank among them and later saves a rival group's princess, the human-looking Dejah Thoris (Traci Lords), from death.
The early part of the film follows the experience of a late 19th-century journalist from Woking, known as "the writer", involved with the landing of a Martian invasion spacecraft. When the crashed cylinder opens, the Martians start killing anything that moves with a "heat ray" weapon. The writer discovers his house is in range of their heat ray and decides to rush his wife and servant to her cousins' home in Leatherhead; once there, he returns in order to return the borrowed cart to its owner, unaware that the invading Martians are now on the move.
Astronauts landing on Venus encounter dangerous creatures and almost meet sexy Venusian women. The astronauts kill a creature that is worshiped by the Venusian women who then attempt to use their powers of nature to kill the astronauts but fail. At last, the astronauts leave the planet and their robot that was burnt by the volcano fire is placed as a god by the Venusian women who have already destroyed the statue of their previous god (a bird).
Abraxas (Jesse Ventura) and Secundus (Sven-Ole Thorsen), are intergalactic police officers, or Finders, from a planet called Sargacia. Their race is physically similar to humans but with an expanded lifespan; Abraxas has been a Finder for almost 10,000 years. Each Finder is equipped with an Answer Box, which serves as a communicator and scanner. It can also detect any object from a distance based on the object's vibration. When testing for the Anti-Life Equation, the subject being scanned will disintegrate if they do not contain the equation.
Kate is dying. She wants reassurance that there is life elsewhere in the Universe. She and Andy go to the one place that may hold the answers to her questions. Alien lights have been seen. Alien ships have been sighted. If she could only come into contact with these foreign forces! The bizarre people who inhabit the area also play a role in Kate and Andy's quest. The one place that may hold the answer is...GROOM LAKE!
Hud Masters (Paul Sloan) is released from prison to hunt down a viral like alien race. He is taken to an agency, where he is partnered with Logan (Colleen Porch) to undergo such a mission. Together they fight their way though a horde of alien infestation in the city, until they reach the leader (Hayley Dumond). Meanwhile, Masters is desperately trying to keep himself from reverting to his violent ways.
A group of pilots in the Canadian wilderness begin to hear strange reports over their radios about planes crashing, cars stalling, and a deadly plague which has gripped the planet. As the plot continues, it's clear that Earth is in the midst of an invasion. The pilots barracade themselves in a cabin in the woods and wait for impending doom.
USS Iowa is on its final voyage before being decommissioned and turning into a floating museum. When USS Enterprise is attacked and destroyed by a mysterious force, World War III looms. The captain of Iowa chases an invisible ship, which they discover to be an alien force waging war on Earth. Only the crew of this last American battleship, stands in their way. (The Iowa's outdated technology is immune to the electromagnetic pulse (EMP) weapons of the alien.)
The story involves the people of Mars, including Momar ("Mom Martian") and Kimar ("King Martian"). They're worried that their children Girmar ("Girl Martian") and Bomar ("Boy Martian") are watching too much Earth television, most notably station KID-TV's interview with Santa Claus in his workshop at the North Pole. Consulting the ancient 800-year-old Martian sage Chochem (a Yiddish word meaning "genius"), they are advised that the children of Mars are growing distracted due to the society's overly rigid structure; from infancy, all their education is fed into their brains through machines and they are not allowed individuality or freedom of thought.