The Space Shuttle returns to earth, but some of the equipment brought back on it begins to behave strangely. Scientists are unsure what is happening, and decide to take all necessary precautions.
During a routine flight, two veteran space shuttle pilots discover an alien artifact and bring it back to earth. It soon turns out to be an extraterrestrial war robot, which is able to recycle any biological or technical material for its own deadly use. The two astronauts are sent to the moon, where Nasa expects to uncover the mystery of the alien robot's origin. They discover an ancient humanoid culture and battle the ultimate threat of the war machines heading to earth.
- 20th July 1969
Sound of austronauts talking and sending information about their moontrip. Suddenly, there is only white noise. Neil Armstrong (Neil Armstrong himself via archived recordings) steps onto the Moon, saying "That's one small step for man, one giant leap for mankind."
Title credits. Some astronauts talking to base. One of the astronauts asks about the weather, and base answers that the weather is perfect, sunny and dry.
Col. Jason Grant (Walter Koenig) is recording himself saying bombastic things about their mission. Meanwhile, Ray Tanner (Bruce Campbell) falls asleep. Jason starts a bell to startle and wake him up. They have a good time and they share their nicknames. Suddenly, the radar contacts something approaching fast. It looks like another spaceship. Jason decides to get into the shuttlesuit and try to enter the ship, even though Chuck Koreman (Robert Kurcz) at ground control had chosen Ray. There are hieroglifics on the outside walls of the ship. There is a hole on the outer layer of the ship, and Jason picks up a container. A kind of dead corpse passes Jason by.
Back to Earth, in a lab, the container and the corpse are brought and studied. They are 14,000 years old. Barnes (John J. Saunders) says that they can't open the container without destroying it because it's made of a strange alloy. Haskell (Reavis Graham) asks Barnes if the president should be informed. Haskell thinks it's a con so that the budget for NASA will get increased.
When it's on its own, the container opens up, and a kind of metalic octopus appears. It smashes a mirror with its sounds and it makes the computers work under its domain. It looks as though they are feeding them information. The corpse looks like a human, and the place of origin is the Moon. There is a kind of overload, and everybody gets trapped on the lift. Haskell doesn't want to write a different report to his own. So Jason insists that there should be another trip to the Moon. The alien octopuss gets hold of some metalic instruments and uses them to give iself some arms.
An assistant (Mariafae Mytnyk) enters the lab and sees the corpse missing from the isolation room. She calls security, but the alien robot kills her and then leaves. Jason and Chuck want Haskell to call George Beck (Tom Case) so that they will work together. A lieutentant (James A. Courtney) and two soldiers (Tony Abruzzo & Tom Whalen) arrive to the lab and find the assistant. They run after the robot, and they have it cornered, but Barnes wants to send a friendly message to it. It shoots Barnes on his arm, so Barnes tells everybody to shoot. The robot is unharmed, and it sends electric rays to kill people. Ray crawls through the air shaft and finaly shoots it on its head: the robot falls to pieces.
Jason Grant's son (Doug Childs) lives in a futuristic mansion with his dad. He loves reading scy-fi comics. The son mentions that the mother is already going out with somebody else. Barnes and Jason meet at Joey's, a night club. Ray flirts with a waitress (Pat Carozzo) who won't serve him any more drinks. Jason arrives and he's drunk. Ray wants to get famous. Ray tells Jason their mission has been approved. Ray is childishly enthusiastic, but Jason is worried.
Once on the Moon again, Jason and Ray moonwalk. Right as they leave their secondary shuttle, another robot appears and moves underground towards the shuttle. With its tentacles, it takes all its electric power. Chuck in Houston tells the astronaut left behind on the main ship, Beck, to be careful. Ray and Jason's moon car gets stuck in the sand. They crawl to a soft steep and they find an alien base. They approach it in their car and see a green light on top. Buried in the sand, Jason finds a human-like skeleton, so they carry guns with them. Behind them, the robot follows them.
Inside the alien base, there are many more skeletons. They think it's a kind of ceremony hall. They open the door with a human-hand touchscreen. Everything lights up. They find a cryogenized woman who wakes up. She tries to shoot them, but Jason takes off his helmet and tells her that they are human. Mera (Leigh Lombardi) holds onto the bracelet in one of the skeletons. The robot lifts the secondary vassel up. Base advises the astronauts to go back to their ship as it's moving and sending strange info. Mera uses its own alien spacesuit to leave the place. A cocroach-like robot attacks them from the ceiling, but the two humans kill it.
Beck directs the buggy to the new location of the shuttle, but it's gone when they arrive there. They follow the trail in the sand. The three find the alien ship, which looks as though it's leaving. The robot appears but Ray can kill it.
Another robot appears. Beck's computer system is not working and the ship falls down to the moon. Ray dies. Jason and Mera walk to the car and they reach a spacetent. There, they kiss each other, and they make love.
Outside, a robot takes Ray's corpse. Again in their spacesuits, Mera and Jason are about to leave, but the robot is using Ray's face. Mera shoots it. Two other robots appear, and they take Mera and Jason. They chain them to the wall in a dungeon-like wall. Jason realises that the robots need people as spare parts. Another robot appears and cuts a piece of cloth from Mera. Jason releases himself and finds a piece of tube and kills the robot, destroying it. He frees Mera. They get into their spacesuits and they find a way out.
Meanwhile, the voices (B.K. Taylor, Jay Scott & Lani Castner) from Houston are sending to space another spaceship, commanded by a woman (Judy Levitt) and piloted by a man (Reuben Yabuku).
Mera and Jason go up in zero gravity looking for the exit. Everybody stares at the alien ship; Jason and Mera see it as well. They try to float towards it. They find their secondary ship in perfect condition. The human ship approaches the alien ship, but the humans are attacked. Jason sets on a time bomb.
Another container appears. On shooting it, Jason sends himself and Mera out to space, so they approach the human ship. The time bomb goes off, destroying the ship. The human ship picks up Mera and Jason.
Jason and Mera are now married living in his luxurious home. She wants to stay on Earth, forever with him.
Jason says that it's over, but somewhere on Earth, a capsule like the one at the beginning opens up. It starts to work and we can see that it's in the perfect location: a car-scrap shop.
As the end credits finish rolling, a brief audio clip is heard of Grant talking to a [[NASA]] official on the phone about the possibility of any debris that may have fallen to Earth in the aftermath of the ship's explosion. The official denies such a thing and assures Grant that anything that would have crashed to Earth would have incinerated upon entry.
--written by KrystelClaire