Forbidden Planet is a 1956 science fiction film directed by Fred M. Wilcox and starring Walter Pidgeon, Anne Francis and Leslie Nielsen. The characters and setting were inspired by Shakespeare's The Tempest, and the plots are very similar.
The film features a number of Oscar-nominated special effects, groundbreaking use of an all-electronic music score, and the first screen appearance of both Robby the Robot and the C-57D flying saucer starship.
In the early 2200s, the United Planets Cruiser C-57D is sent to the planet Altair IV in the Altair star system, sixteen light years from Earth, to find out what happened to a colony expedition sent out some twenty years earlier. At the end of the year-long voyage, Commander John J. Adams (Leslie Nielsen) contacts Dr. Edward Morbius (Walter Pidgeon), the expedition's philologist, who warns him to stay away, but refuses to give a reason.
Upon landing, the crew is met by Robby the Robot, who takes Adams, his first officer, Lieutenant Jerry Farman (Jack Kelly), and Lieutenant "Doc" Ostrow (Warren Stevens) to Morbius' home. Morbius explains that a year after the expedition's arrival, some unknown force wiped out nearly everyone in his party, and vaporized their starship as the last survivors tried to take off. Only he, his wife (who later died of natural causes) and his infant daughter survived. Morbius fears that the same fate may await the crew of the C-57D.
The officers are dazzled by the house and its array of technology, advanced beyond anything known to mankind, including Robby, which Morbius claims to have "tinkered ... together during my first months up here". Adams is skeptical, reminding Morbius that his field is philology, not physical science.
Morbius' nineteen-year-old daughter Altaira (Anne Francis) appears. She has grown up, like Shakespeare's Miranda, not knowing any man except her father. She is therefore very curious to learn about human relations. Several officers and men are more than willing to help with her education, but Adams keeps them in line, much to Altaira's puzzlement.
Morbius tells Adams he has been reconstructing the history and science of the Krell, the long-extinct natives. They had possessed a technology and society a million years ahead of that of humanity, but had all died 200,000 years before in a single night of inexplicable destruction. He shows his guests what he calls a "plastic educator". His first use of it put him into a coma for almost two days, but also doubled his intellect, enabling him to build Robby and the rest of the wondrous devices. Morbius also takes them on a tour of a cube-shaped underground Krell installation, 20 miles on a side, powered by 9200 thermonuclear reactors, which has been operating and self-repairing since the extinction of the Krell. When asked its purpose, Morbius is evasive. He mentions, however, that it reconfigured itself some 16 years previously.
One night, a valuable piece of equipment in the ship is damaged, though the sentries report they saw no intruders. In response, a force-field fence is set up to protect the ship. However, it proves to be useless. The unseen thing returns, shorts out the fence, and kills Chief Engineer Quinn (Richard Anderson), literally tearing his body to pieces.
Initially suspicion falls on Robby, but he is ruled out when the ship's cook provides an alibi (he was drinking with Robby, after the latter had synthesised 60 gallons of "Kansas City" Bourbon for him). A plaster cast is made from one of the huge footprints found on the ground afterwards. Dr. Ostrow is puzzled by what he can deduce from it; the creature appears to violate all known evolutionary laws.
The intruder comes back the following night and is discovered to be invisible. It is seen only in outline when it encounters the fence and fire from energy guns flickers over it. It kills several more crewmen, including Farman. At his home, Morbius is having a nightmare when he is awakened by Altaira's scream. At that moment, the invisible attacker vanishes.
While Adams confronts Morbius, Ostrow sneaks in and uses the educator. Before he dies from its effects, he gasps out his revelation: the vast machine was designed to let the Krell materialize anything they wanted at a mere thought. "But the Krell forgot one thing! Monsters, John! Monsters from the id!" Though the Krell considered themselves civilized, their subconscious minds were unleashed to act out their darkest urges, resulting in their destruction.
When Morbius objects that there are no Krell to generate the creature, Adams contends that Morbius's subconscious is responsible, and that it caused the deaths of the Bellerophon party when they voted to return to Earth. Morbius deepest desire was to study the Krell and the machine fulfilled that wish.
When Altaira declares her love for Adams in defiance of her father, the monster comes for them, breaking into the house and melting through the near-indestructible door of the Krell vault where Adams, Altaira and Morbius have taken refuge. Morbius finally accepts the awful truth and tries to renounce his creation. When he is mortally injured, the monster disappears. As Morbius lies dying, he directs Adams to press a lever which sets the Krell machine to destroy itself. Adams, Altaira, Robby, and the surviving crew witness the destruction of the planet from a safe distance in space.
† Not credited on-screen.
The film sets were constructed at an MGM sound stage on the Culver City lot and were designed by Cedric Gibbons and Arthur Longeran. The entire film was interior studio-bound, without any outdoor photography. All outdoor scenes were simulated with sets and visual effects.
A full-size mock up of three quarters of the C-57D was built to suggest its full width of 170 ft (51 m). This was surrounded by a huge painted diorama of the desert landscape of Altair IV. This set took up all the space in an Culver City sound stage. This was the first film in which humans are depicted traveling in flying saucers of their own construction. The ship was reused in several episodes of the original Twilight Zone, which was also filmed at the MGM studios.
At about $125,000, Robby the Robot was a very expensive film prop for the time. The electrically-controlled landcar or "dune buggy" driven by Robby and the tractor-tow truck offloaded from the spaceship were also built for the film. Robbie was later featured in the film The Invisible Boy and appeared in numerous television series and movies. Like the C-57D, Robby (and his vehicle) appeared in episodes of The Twilight Zone.
The animated sequences, especially the attack of the id monster, were created by veteran animator Joshua Meador, who was lent to MGM by Walt Disney Pictures. Curiously, shots showing the shape of the invisible monster outlined in the blaster beams were evidently removed from some prints shown on television — presumably because its appearance was considered too terrifying for younger viewers — and it was many years before these shots were restored. The id monster vaguely resembles the Looney Tunes character "Gossamer". A close look at the creature shows it to have a small goatee beard, suggesting that it is connected to Dr. Morbius, the only character with this feature.
Helen Rose, who made some miniskirts for actress Anne Francis, is sometimes credited with inventing the garment.
Using equations from the 1948 book, Cybernetics: Or, Control and Communication in the Animal and the Machine by mathematician Norbert Wiener, Louis Barron constructed the electronic circuits which he used to generate the "bleeps, blurps, whirs, whines, throbs, hums and screeches". Most of the tonalities were generated using a circuit called a ring modulator. After recording the base sounds, the Barrons further manipulated the material by adding effects, such as reverberation and delay, and reversing or changing the speed of certain sounds.
As Louis and Bebe Barron did not belong to the Musicians' Union, their work was not considered for an Academy Award, in either the soundtrack or special effects category. Curiously, MGM avoided producing a soundtrack album when the film was first released. However, film composer-conductor David Rose released a 45-rpm single of his original main title theme, which he had recorded at MGM Studios in Culver City, California in March 1956. This theme had been discarded when Rose, who had originally been contracted to compose the film’s music score in 1955, was discharged between Christmas 1955 and New Year’s by Dore Schary.
The innovative soundtrack was finally released on a vinyl LP album by the Barrons for the film's 20th anniversary in 1976, on their own PLANET Records label (later changed to SMALL PLANET Records and distributed by GNP Crescendo Records) and, later, on a music CD in 1986 for its 30th Anniversary: with a six-page colour booklet containing images from Forbidden Planet plus liner notes from the composers, Louis and Bebe Barron, and Bill Malone.