It is the year 2200, and Commander Adams (Leslie Nielson) directs his spaceship to an earth-like planet called Altair-4 in search of a former earth colony, out of contact for many years. They receive a transmission from Dr. Morbius, telling them to go away, but they insist on landing. A huge robot named Robby brings Adams and two crew members to the home of Dr. Morbius (Walter Pidgeon). Morbius tells them that, with the exception of Morbius and his wife, everyone else in the colony was violently killed by an unseen force, which then disappeared. Now widowed, he lives with his daughter, Alta (Anne Francis) and Robby. Alta has never seen any human other than her father. Morbius explains that a great race once lived on the planet, and he has studied their artifacts. In an attempt to use their minds and spirits to create something, he inadvertently created a creature made up of their fears and anger. It is called the Id. It reappeared when the colonists arrived, out of their subconscious urges. And, with the arrival of the crew from earth, it has come back again. The invisible being damages the spacecraft and kills three of the men before Morbius, realizing that the Id came from within him, renounces that part of himself, destroying both of them. Adams and Alta escape with the crew before the planet explodes.