(1956 c 98')
In the future a human spacecraft lands on a planet where a father and his daughter live with extremely advanced technology aiding them.
In 2200 humans are exploring deep space. A flying saucer travels to the planetary system of the star Altair. Commander J. J. Adams (Leslie Nielsen) goes with Lt. Doc Ostrow (Warren Stevens), Lt. Jerry Farman (Jack Kelly), and Chief Quinn (Richard Anderson), and they are transported to a slower speed. They see the Altair sun and orbit the fourth planet. Adams says that twenty years ago Bellerophon landed there, and they are to search for survivors. Their flying saucer enters the atmosphere and finds radar coming from an area twenty miles square. By radio they hear Dr. Edward Morbius (Walter Pidgeon) of the Bellerophon, and he says he needs no assistance. Adams says he is to explore the situation. Morbius advises him to leave and warns him he cannot guarantee their safety. Adams asks for landing guidance, and Morbius gives him the coordinates but warns him again. Adams orders his crew to wear side-arms in a security alert.
The flying saucer lands on the ground of a barren planet. Adams leaves Quinn in command on the ship and leads men on the ground. They see a robot car arrive, and Robby the robot welcomes them and says he will transport them. The Cook (Earl Holliman) asks if it is male or female, and Robby says that has no meaning. Adams, Doc, and Jerry sit in the car, and Robby takes them to the home of Morbius, who finds himself besieged by fellow creatures. He says he is a recluse, but he invites them for lunch.
They like the lunch that Robby cooked. Morbius explains how Robby learns about human food and can dispose of things too. Morbius says Robby is only a tool with a built-in safety factor. Morbius borrows a gun and has Robby fire it. Then he has Robby point it at the commander and says, “Fire,” but Robby starts to blow his circuit while his conscience stops him. Morbius cancels the order. Morbius admits he made this robot. Adams is amazed that Robby is beyond earth science. Morbius closes the steel shutters and then opens them again. He says he has no need of military assistance and suggests they return to their ship. Adams says they want to interview the others. Morbius says his wife and he came there, but the others died. His wife died of natural causes two months later. They ask how the others died, and Morbius says some force tore them apart. He says he has not been bothered since then, though he feels its presence. Alta (Anne Francis) comes in wearing a short dress, and she likes Doc and Jerry especially. Morbius says she has never seen another human except him before. Alta asks Jerry if he is like Robby. She says the three are exceptions from Earth. Jerry says that Adams is notorious with girls. Morbius tells her they are asking about her liberty, whether she wants to visit Earth. She whistles silently, and two young deer come, followed by a tame tiger. Morbius says it is still wild outside of her influence. Adams gets a call from the ship and shows them they are all right with the viewer. Adams says he must contact base for instructions regarding the crew that died. He says they need to build a transmitter which will take ten days. Morbius offers him the materials needed by the next day. He shows him the cemetery he dug. Adams thanks him, and they go back with Robby to their ship.
The crew is working on building the transmitter, and Robby brings the shielding. Jerry talks to Alta, who says her father told her to stay away from the ship. Adams sees Jerry and Alta walk off and goes to check the transmitter with Quinn. Robby pulled the Cook away with a magnet. The Cook asks him for real bourbon. Robby analyzes it and offers him sixty gallons.
Jerry asks Alta for a kiss and says it stimulates the whole system. He offers to show her and kisses her. She asks if that is all there is, and he kisses her again. She asks for one more. She says she did not notice any stimulation. He puts her arms around him and tries again. Adams intervenes and sends Jerry to the ship. Adams warns Alta not to dress like that and suggests she put on something more. She asks him not to look at her like that. She says she and Jerry were trying to get some stimulation by hugging and kissing. Adams warns her that his men have been locked up in hyper-space for 378 days. He tells her to go and says he will put guards on the guards.
Alta tells Morbius what Adams said to her. She does not want to see him again. Morbius says goodnight. Alta calls in Robby and asks him for a new dress in which nothing will show. He says he will have it for her by breakfast.
Jerry and a crewman look at the two moons, and then they hear something strange. The next morning Adams tells three crewmen that the ship was entered last night. Quinn tells Adams that he will need time to rebuild the modulator. Adams leaves Jerry there and goes off with Doc in their truck.
In the house Robby uses a ray to chase a monkey away. Adams and Doc arrive and ask for Morbius. Robby says he is in his study behind a door. Alta is bathing in a pool, and Adams goes to see her. She invites him to come in, and he says he did not bring his bathing suit. She asks what that is. She gets out to dress, and he turns his back. She says he won’t have to look at her anymore. She says she did not expect to see him again. He apologizes. She comes out in a long dress and jewel necklaces. She asks if he does not like her personally. He says she looks beautiful. She asks him to kiss her like everyone else. She tells him what she has studied. He kisses her, and she responds well. The tiger appears, and she says he is her friend. The tiger leaps, and Adams vaporizes it with his gun. She asks why the tiger did not recognize her.
Adams goes back and asks Doc if Morbius has come out. When he gets near the door, it opens. They go in and look at plans on the desk. Morbius appears and tells them where they will find the silver. Adams says their ship was entered last night. Morbius tells them to sit down and explains that this planet had an ancient race of beings called the Krell, who were a million years ahead of humans. They had conquered their baser selves and had banished sickness and crime. They had been to Earth long ago. Then suddenly they perished in a single night. After two thousand centuries nothing remains above ground. He shows them a triangular arch and says that is the only remnant. He plays a recording of Krell musicians from a half million years ago. He takes them through a tunnel and shows them other artifacts. He has Adams try his blaster on their metal, but it has no effect. Morbius opens the door, and they enter one of their laboratories. He shows them a screen that will show all their history and other knowledge. He says he comes there every day to learn from them. He also shows them a plastic educator for the young. He connects it to his head, and it shows his brain waves. He says Krell would consider him a moron, but his I.Q. is 183. He creates a small three-dimensional image of Alta. Morbius lets them test their intelligence. Doc says his I.Q. is 161, but he was only a third of Morbius. Adams does worse. Morbius stops him from trying to image because it caused the death of others. Morbius was shocked the first time but says it doubled his mental capacity. He tells them about the Krell project to live without instruments. Morbius says that equipment is 2,000 centuries old. They ask about the source of energy. Morbius says he could find no direct wiring. They realize that the potential there is astronomical. Morbius takes him in a car through a large structure. He says it is forty miles across, and they look into a ventilator shaft. He says it has 7800 levels, and there are 400 other shafts. He says the machinery maintains itself. He shows them one of the power units, but they have to look at it in a mirror.
At the ship Jerry asks the Bosun (George Wallace) to test the transmitter. The Cook asks Jerry if he can walk outside the parameters. Jerry warns him to get back before the skipper. The cook trips and finds 480 bottles of bourbon, and he drinks some and thanks Robby. The Cook picks up some bottles. The new system has an electrical discharge, and Jerry says they will check it in the morning. Footsteps of a heavy creature are seen. Jerry and a crewman hear a man scream.
At his desk Morbius tells Adams that he will not be dictated to. Adams says this scientific find must be taken to the planetary command. Morbius says he has considered the problem and that mankind is not yet ready for this power. He says he will dispense what his conscience allows. Adams gets a call from Jerry who says that the Chief was murdered. Adams and Doc leave, and Morbius says it has started again.
In the ship Adams and Doc are shown the imprint of the footsteps. Doc says it is not natural. Jerry brings in the Cook for discipline. Adams asks if he had permission to get drunk. The Cook says it left no hangover and says he got it from the robot. Adams dismisses him and concludes the robot could not have done it.
They perform a burial, and Adams dismisses the company. Morbius and Alta are there. Morbius says he begged them not to land on the planet. He warns them the next attack will be more deadly and general. Adams asks how he knows that, and Morbius says he has a premonition. Morbius and Alta leave on Robby’s car.
By the ship Adams orders the batteries activated for a test. They fire rays, and Adams says it is good. Adams apologizes to Jerry, who says she picked the right man. They get a message that radar picked up something. They fire the rays at it. A message says it is coming again. They fire again at the invisible monster that reacts. It kills two shooters and then Jerry goes forward to shoot and is burned up.
Morbius reacts at a table, and Alta comes in crying about a bad dream. She asks him to help, but he says he can do nothing as long as they remain there willfully.
Adams says it went away for some reason and may be back. Doc says nothing could withstand that force; it must be renewing itself each microsecond. Adams says that one of them must get into the Krell lab and take the brain boost. Adams puts Bosun in charge and orders him to lift off if the creature comes back and then go back to Earth base. Bosun orders the crew to get on the ship.
Adams and Doc take the truck to the house. Adams says he will go first on the I.Q. booster. At the door Robby tells them he is to admit no one at that hour. The robot neutralizes their blasters. Alta comes and tells Robby to let them in. Adams embraces her and says they were attacked. She says she cannot explain it. She does not want him to leave. He wants her to go with him, but she says no. She tells him to go and kisses him. Adams asks Doc to talk sense to her. He turns and sees Robby carrying Doc. He lays him down. Doc tells Adams the Krell forgot about monsters from the id. Doc dies. Morbius says he was a fool and should be buried with the other victims of greed and folly. Alta tells Morbius she has chosen to go with Adams, who asks Morbius what is the id. Morbius says it is an obsolete term for the elementary basis of the subconscious mind. Adams says what that Krell machinery could do. Morbius realizes that even the Krell must have evolved from a primitive beast. Adams says they created a machine that could never be shut down. They could take revenge and kill. Morbius says the fallacy is that the last Krell died long ago, but a living monster is still on the planet. Adams says his mind does not draw the conclusion. A message warns them, and they see a path of destruction. Morbius closes the steel shutters. Adams tells Morbius that the creature out there is him. Morbius asks Alta to tell it that she does not love that man. Morbius asks Robby to keep it out. Adams says it is no use; he knows that it is his other self.
The three run through the tunnel into the laboratory, and Morbius says they are still in there. Morbius asks Adams why he scrambled the code. Adams holds Morbius and tells him that his secret id murdered the Bellerophon crew. His subconscious sent out the death monster, and his monster is punishing his daughter for her disobedience. The machinery will supply his monster with whatever power it needs to reach them. The door is turning red and melting. Alta tells her father to be noble like the Krell. Morbius cries that he is guilty and cannot stop his evil self. Morbius says to stop and that he denies it and gives it up. He collapses, and Alta comforts him. Morbius tells Adams to throw a switch. Morbius says that in 24 hours they must be million of miles away because there will be a chain reaction that cannot be reversed.
The flying saucer flies through space. Adams with Alta tells the crew they are clear now. They watch as the planet Altair explodes. Adams speaks of the great moment of Krell that humans may reach in a million years. He says that the memory of her father will remind them that they are not God.
This science fiction drama takes off from the story in Shakespeare’s Tempest. No matter how advanced creatures may become, they still must be aware of their basic self which contains primitive drives in the subconscious that functions in the body. As humans are entering the nuclear space age, they must learn to control their destructive tendencies.